Maximum Memory in 32-bit Windows Vista

Follow-up–I answer some reader questions about this topic here. Read this article first, though.


Hi, I found your website today during a search on Vista. My question is will 32 bit Vista Ultimate support more RAM? IE 4 or 3?


I thought this was a slam-dunk, but it turns out to be a damn good question! The short answer is, the practical upper limit is usually about 3GB of RAM.

The long answer takes some explanation… Here’s the official answer from Microsoft:

  • 32-bit versions of Windows Vista Home Basic, Home Premium, Business, Enterprise, and Ultimate: 4GB
  • 32-bit Windows Vista Starter: 1GB
  • 64-bit versions of Windows Vista Home Basic: 8GB
  • 64-bit versions of Windows Vista Home Premium: 16GB
  • 64-bit versions of Windows Vista Business, Enterprise, and Ultimate: 128GB

So I search around a little to find some real-world experiences for people with 4GB installed:

This paper from HP helps explain it–the platform can theoretically support the full 4GB, but your hardware is going to allocate some of the address space (not the physical RAM) to the PCI bus, the video adapter memory address space, and other resources. 32-bit OSs need to use part of the full 4GB address space to address these resources, subtracting from the maximum memory you have available to the OS and applications:

The PCI memory addresses starting down from 4 GB are used for things like the BIOS, IO cards, networking, PCI hubs, bus bridges, PCI-Express, and video/graphics cards. The BIOS takes up about 512 KB starting from the very top address. Then each of the other items mentioned are allocated address ranges below the BIOS range. The largest block of addresses is allocated for today’s high performance graphics cards which need addresses for at least the amount of memory on the graphics card. The net result is that a high performance x86-based computer may allocate 512 MB to more than 1 GB for the PCI memory address range before any RAM (physical user memory) addresses are allocated.

So, if your video adapter has 512MB of RAM (like mine does), your maximum memory is going to at most be 3.5GB, because Vista has to use 512MB of that address space to address your video memory. It’ll actually be lower than the 3.5GB because there are other hardware resources that need address space, too. So, it never hurts to fill your computer with 4GB of RAM–you’ll definitely get the max, but you won’t be able to address it all. You probably won’t be able to address much more than 3GB, and you might not be able to address more than 2GB.
The paper also mentions something interesting about 64-bit computers. Basically, depending on the hardware, you might be limited to 4GB of RAM even if you install 64-bit Windows Vista:

Windows XP Professional x64 Edition uses 64-bit addressing enabling virtually the entire amount of installed RAM to be made available on computers that have large address infrastructures (where the entire system has more than 4 GB addressing capabilities via the processor, chipset, physical memory capacity, etc). The HP xw4300, xw6200, xw8200 and xw9300 Workstations have the required infrastructures and even the PCI memory address range is recovered by re-mapping it above the top of physical memory.

Thanks for the great question. If you’re using 4GB of RAM with 32-bit Vista, add a comment and let us know about your experiences.

Update 4/9/07: To address the lively Linux-vs-Windows debate in the comments, it seems wildly irrelevant. First, it’s still true that any 32-bit OS needs to use part of the 4GB address space to address resources. However, you’re right that Physical Address Extension (PAE) can be used to address more than 4GB from 32-bit OSs–this is true of some Linux distributions and many 32-bit Windows OSs. Here’s the catch: applications have to be written specifically to take advantage of PAE, and the only applications that do that are very specialized tools or server applications like SQL Server, which don’t typically require that much RAM when running on a desktop OS. So, PAE won’t make your Photoshop or video editing app any faster, and it isn’t nearly as useful as it sounds. While 64-bit Windows Vista isn’t perfect, it will give you access to your full address space, and you’re bound to have far fewer application compatibility problems (and get more out of your memory) than you would with 32-bit Linux and PAE.

Oh, and take a break from stressing about OS limitations, and read something funny.

This entry was posted in Hardware, Performance, Reader Questions by Tony Northrup. Bookmark the permalink.

About Tony Northrup

Tony Northrup, MVP, MCITP, MCPD, MCSE, MCTS, and CISSP, is a Windows consultant and author living in Waterford, Connecticut, in the United States. Tony started programming before Windows 1.0 was released, but has focused on Windows administration and development for the last fifteen years. He has written more than two dozen books covering Windows development, networking, and security. Among other titles, Tony is coauthor of the Windows 7 Resource Kit, the Windows Vista Resource Kit, and Windows Server 2008 Networking and Network Access Protection (NAP). When he's not writing, Tony enjoys photography, travel, and being awesome. Tony lives with his girlfriend, Chelsea, her daughter, Madelyn, and three dogs. You can learn more about Tony by visiting his personal website at and his photography portfolio at

183 thoughts on “Maximum Memory in 32-bit Windows Vista

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  2. Pingback: upgrade2vista » Blog Archive » Maximum Memory in 32-bit Windows Vista

  3. I did a clean install of Vista Ultimate Edition (final) on my 3 month old Dell Dimension 9200 which has 4Gb RAM.

    4Gb shows in the updated BIOS, but only 3.1Gb is apparently visible by Vista. Basically the same when I had XP installed.

    My Windows Experience basescore is 5.3, by the way.

  4. running vista home premium on asus p5b-e, 4gb installed, 3gb available in bios and in windows. is this normal? should i complain? or is this normal?

  5. Kosta, you should definitely see more than 3GB available to the BIOS (Windows, maybe not, but the BIOS should see more). For some reason, your motherboard isn’t detecting all your memory. Verify that the motherboard supports more than 3GB, and try reseating each memory chip.

  6. I installed Vista Premium x64 and It saw the full 4GB. THe issues I was having where with nVidia drivers and SLi. I have since gone to the x86 version. SLi now works fine, but I am only able to see 2.5GB of RAM. What’s the deal?

    • Dude just told you, its due to “other hardware” taking it over for its own addressing purposes. If you can see 2.8, 3.1, or 3.5 who cares, its f*cking working isn’t?

  7. Is there no work around? I am going to format again and hope that I can get the nVidia driver to work this time… What a waste of time!!

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  9. Installed Vista Ultimate 32-bit on my system with 4GB ram, only shows 3GB available in Windows. Was running Windows XP Pro x64 and always had 4GB available…

  10. I’ve got 4GB of ram installed in my machine. Bios recognizes all of it but Windows XP Pro 32bit as well as Vista Business 32bit only see 3.25GB of it. I have a 512MB video card installed so that uses up a bit of addressing space. While I’m sure 3.25GB will be enough for now, I don’t like the fact that I’m more or less wasting 768MB of ram. I’ll be upgrading to Vista x64 asap.

    • It’s not wasting it!!! Jesus F’in Chirst! The level of ignorance is appalling. The other ram you can’t see via Task Manager is being put to plenty of use. You like being able to see your screen don’t you or hearing music etc. don’t you?

      • Britton, you not only have a potty mouth, you seem to be completely void of any ability at persuasion. Flamers like you don’t help anyone. Read ‘How to Win Friends and Influence People’ if you every want anyone to take you seriously…. ;-)

  11. I have 4Gb of Ram installed on My Beast, My Video Card is a GX2 with 1GB of Available Memory, I am running Vista Ultimate

    But for some reason my system only shows 2.50 GB available System Memory. Weird! I was under the impression that I should have 4GB available.

    Anywho I ran Vista U 64x and there it was 4GB available for System Memory.

    I would like to know what is going on here. From what I gathered Vista 32 bit should be Displaying 3Gb of available system memory since I am using a 1Gb Video Card, if thats the case where is my other 500 Megs????

    When I boot it shows 4GB available.

    I was running 64bit Vista U

  12. Pingback: Brian Tucker : Dell XPS M1710 & Vista Ultimate

  13. Well now. That explains alot. That explains why in XP Pro my 4 GB box only recognizes 2.75 GB, whereas my Vista 32-bit Ulitmate edition recognizes 3 GB.

  14. I’m also running a P5B-E and only seeing 3gb in BIOS and in windows. I have the latest BIOS also.

    CPU-Z sees all 4gb of it but BIOS and XP wont.

    What is going on?

  15. Hey Squidy,

    I have the same problem with the P5B-Deluxe. So i enabled the ‘Remap Memory’ function.. Bios now sees 4096MB. BUT – Windows now sees only 2GB!!! (without remap, Vista & bios sees 3GB).

    So i thought, hey enable PAE in vista. Nothing! Is it a Vista PAE problem or a motherboard problem?

  16. Windows Ultimate with 4GB ram, dual Nvidia 8800GTX running SLI with a total of 1.5GB of memory. Windows is showing 2.5GB RAM, freaked me out until I saw this page, thanks!

  17. has any one tested a SD card or USB memory ram with Vista to be treaded as ram… first thought seems it would slow system to access memory as RAM via a pci->usb channel..

  18. Does all this mean that on a Dell M1710 with a 512mb video card, Vista Ultimate (32b), and 2GB of Ram, one is likely to see only 1.4 GB of RAM or less, since Vista needs to match the video RAM allotment with RAM memory?

    Also, does having a 4GB or higher ReadyBoost enabled USB drive help in any of these metrics, be it on a system with 2GB of RAM or 4 GB?


  19. Pingback: Reader Questions: Why Can’t I see all 4GB of RAM? - Windows Vista help

  20. PEOPLE who own asus p5b-boards
    Check your manual…. it states if you have 4 1 gig sticks in the board, it will only see 3 gigs of ram, if you have 4, 2gig stick to make 8, you will only see 7…. i do not know though, if all the ram can be used….. i have installed vista 32 and 64 bit ultimate on a dual boot and the both only still see 3 gigs as with xp. i have not messed with the remap bios option though….. btw my board is the p5b-premium

  21. Pingback: Reader Question: 32-Bit Vista Memory Limits - Windows Vista help

  22. I browsed through some of the posts and I don’t think anyone actualy explained it. The reason you are not seeing all your ram has nothing to do with the brand of OS. It has to do with the Kernel. Each bit of memmory needs to have an address. A 32bit Kernal allows for addresses to have 32 bits where as a 64 can be a 64bit address. The 64 bit addresses are longer allowing for more possible addresses thus allowing you to see all your memory. I hope that can explain it a little better.

  23. Installed 6 GB RAM on IBM Thinkcenter with “Out of the Box Vista 32 Ultimate” shows 3082 MB RAM


  24. So if you installed “Out of the Box Vista 32 Ultimate” you have a 32 bit kernel. Like I mentioned above you are limited by physical addressing.

    6 gig of ram requires literaly 51,539,607,552 adresses for every bit. Thats 8 bits per byte, 1024 bytes per KB etc. It’s not taking into account any other hardware that reserves memory space. You are 17,179,869,184 short at minimum not counting other hardware.

    In short 32 bit kernel will allow you to address roughly 4 gig of ram less other reserved.

    32 bit = 34,359,738,368 addresses.
    64 bit = 1,099,511,627,776 addresses

    See the difference?

    If by out of the box you mean it came with my shiney new PC and I got ripped off because retail windows ultimate comes with both 32bit and 64bit in the same box than I am sorry you wasted your money on that pc and the extra ram you can’t use. If it came with 32 bit installed chances are you dont have a 64 bit pc. Your only option would be to try /pae switch. I don’y know if it works with vista though

    • Or man up and bite the bullet. Install a x64 bit client and get those Address slots.

    • You had this right.
      32-bit can address: 4294967296 bytes ~or~ 2^32 bytes ~or~ 4GB ~or~ 34,359,738,368 addresses…. however you want to write it

      You had this wrong.
      64-bit can address: 18,446,744,073,709,551,616 bytes ~or~ 2^64 bytes ~or~ 1024ZB ~or~ 147,573,952,589,676,412,928 addresses

      And yes, that’s ZB (Zettabyte). Currently, the AMD64 architecture only has 52-bits to address physical memory, but that’s still 4PB (Petabytes), which is 4,096 GB…

      Byte -> Kilobyte -> Megabyte -> Gigabyte -> Petabyte -> Exabyte -> Zettabyte -> Yottabyte

      Hope you notice the REAL difference in 32-bit vs 64-bit… Granted, due to Microsoft’s licensing, I doubt you’ll ever see Windows be able to access that much memory… Linux can already ;-)

      • Actually

        “Byte -> Kilobyte -> Megabyte -> Gigabyte -> Petabyte -> Exabyte -> Zettabyte -> Yottabyte”

        is not correct, you forgot Terabyte

        Byte -> Kilobyte -> Megabyte -> Gigabyte ->Terabyte -> Petabyte -> Exabyte -> Zettabyte -> Yottabyte

        so “but that’s still 4PB (Petabytes), which is 4,096 GB…” == “but that’s still 4PB (Petabytes), which is 4,096 TB…”

  25. how i wish i have a unit like yours :’( but i’m just a poor guy from a third world country, i can’t afford that much. i’m soaking in here. my unit have only 512mb or ram. (default from factory) if anyone of you is merciful enough can you give me one of your memory module (just kidding). take care all.

  26. I have Biostar NF4st-A9 mainboard loaded 4gb ddr 400 found that the bios showed 3.4gb and windows vista 32 bit showed 2.8gb
    Updated Bios -recognises the 4gb but vista now shows only 2gb
    VGA card Geforce 6600 256m

  27. Have asrock 939-dual sata2 vista 32 only showing 2559 of 4gb dual channel memory, turned off memory hole in bios and got 2927 showing. If your bios has ability to memory map (only some do) apparently this can help by shifting some of the resources eaten up by pci devices to address’s above the 4gb mapped area. Thus increasing your ram available to windows applications.

    Don’t know if this will help anyone, but worth a try.

  28. Read what I said. It is also posted at the top of the page from HP said almost exactly the same way.

  29. It’s disappointing that Vista doesn’t support PAE properly (and MS even disabled PAE support for Windows XP with SP2 AFAIR).
    32-bit-Linux can utilize up to 64 GB RAM through PAE just fine. PAE has been around since the Pentium Pro.

  30. Now it all makes sense. My video card has 768MB and I am showing 3.25GB of RAM out of 4GB. Vista32 btw.

  31. This is just another topic that shows Linux is a better OS than MS. Security/Performance and even memory management..Why should we keep paying MS for an OS that is not even better than Linux of 5 years ago??

  32. Hello Sixlime,

    Why do you keep sticking to the 32 bit crap on the OS. Linux is also 32 bit but can see 64GB!! So the issue is not only the os but what MS puts into it like support for PAE. This just is sad that most PC today can have 8GB very cheap but now are waiting for the OS to9 catch up from MS. I run Vista 64 but it is slow and crappy in support for SW!!!

    How long before MS releases another version with PAE. This will give us a chance to pay for it!! WOW like they gave us some new feature that is old as dirt!! Good Luck MS!!!

  33. Because the topic was on windows OS not linux. Windows with /pae also could support more than 4 gig the same way linux dose. However it dose not work with all MS operating systems.

    So basicly what you are saying is that I am right as linux makes use of the /pae ( physical adress extention ) in order to adress more than the 4 gig limit of a 32 bit OS.

  34. Hello sixlime,

    No I am correcting you as you state that the MAX a 32 bit OS can address is 4GB as if this is a hard physical limit of a 32 bit OS as exampled by you above. I was using Linux as an example to prove you incorrect as a 32 bit OS can (by using) PAE address much more than you keep trying to say. The fact that MS can not, or wants to sell you this is my other point.

  35. Yes but you are again proving me right. Read again. I mentioned trying /pae in my second post. Fact is without pae a 32bit kernel IS limited to 4 gig.

  36. You are trying to argue that it can not count/address any number higher than 4gb. So how do you explain other 32 bit OS that can address higher.

    Using PAE the OS needs to somehow address larger than 4gb numbers? What are you trying to say about PAE? I think you do not understand how PAE and how memory space works?

    When you figure this out you will see that it is using another linked address space to get above your so called max of 34,359,738,368. So in the end the 32bit OS can address more than 34,359,738,368 !!

    You need to explain that it is Microsoft’s choice to hamper the 32bit OS by not using the virtual address space every other OS does. I do not know of any other 32 bit modern OS that is limited like MS. I guess so that you can pay MS to get HOME PREMIUM!!!!!

    When you agree that a 32bit OS can using virtual address reach more than 4GB then you will see that your stance is merely based in theory and not real world.

    Good Luck.

  37. No I understand that pae uses virtual adress. This still dose not change the fact that without it a 32bit kernal can not adress more than 4 gig. This is what you do not understand. Wether Microsoft decides to make you spend more to get it dose not change the fact you still need it to get above 4 gig with a 32 bit kernel.

    You somehow think that numbers do not add up and that the numbers are only theory. Like you said other os can address more. This is because they use pae or are 64bit. Not because they can mysticly change the laws of physics and fit more into the same space.

  38. IF you would just inform everyone correctly that it is Microsoft 32 bit OS that is limited to 4gb then you advice would be correct. Instead you stated that all 32bit OS were the same.

    You would have been more accurate to say that 32 could only count to 4gb but methods exist to address higher.

    Also, stop trying to separate the OS from the hardware. They both are interconnected. For example, if I hook up USB1 device to USB2 port will the OS still run at USB2 speeds? Is it hardware or SW or both that sets the features performance?

    Same with PAE, it is available to all OS that run on Intel. So the fact that other 32OS use PAE prove to you that it is capable to address more than 4Gb just not count higher!!

    Good Luck

  39. Yes but you continue to prove me right. I did mention pae in my scond post as an option for a 32bit os. Nowhere dose it say All OS in any of my posts. If it would make you feel better, yes I did not explain how pae works. This dosen’t change the fact still.

    PS like I said earlier this topic is windows not linux

  40. To Matt!

    I also have a problems running SLI on Vista H.P. X64 with 4 GB ram, I get a black screen after reboot! But you can run SLI with 2 GB of Memory!

    It’s not only a Nvidia SLI, ATI’s Crossfire has (or had) the same problem..
    I think it would be a question of time, till it would be solved!


  41. Oh dear god…so many people are so wrong on this and yet “debate it” as if they knew what they are talking about. PAE is a HARDWARE feature in certain CPUs and in the chipset. MS fully supports it in XP, server 2003 and Vista. I have it on right now in XP SP2. Its amazing how people spread misinformation. There is no difference between Linux, Mac OS and Windows in this regard. 32 bit platform has PHYSICAL LIMITS. These PHYSICAL LIMITS have been somewhat circumvented by, AS USUAL, a hardware PAGING hack. This generation it is known as PAE. PAE extends address space to 36 bit. For those who cant do math (many on this thread), thats 64GB. SURPRISE! The “magic number” that “mighty Linux” supports. Well guess what? WINDOWS SUPPORTS THE SAME AMOUNT OF RAM UNDER PAE SINCE THAT IS THE PAE LIMIT! Since Linux runs on essentially the same damn hardware as Windows and since PAE is PAE, THERE IS NO DIFFERENCE.

    PAE is a pretty ugly hack, though, and lots of drivers/code dont like it no matter what the platform is. If you really need large RAM amounts, its time to jump to a 64 bit OS. Remember all the idiots that ran around saying “no one needed 64 bit”? Well now you can call them morons and make a note to take with a BIG GRAIN of salt most of the “advice” and ranting on the web.

    This is all just basic math and really shouldnt be a mystery to anyone. It just shows that average users are now wading into waters where they really dont belong when people are enraged, shocked and surprised that the 4GB of RAM the blew their money on isnt fully available to them on a 32bit OS that has a MAX LIMIT of 4GB of virtual address space.

    Even with PAE, it just builds a table of 4GB address space blocks and pages them in and out of the 36 bit block of physical RAM.

  42. “Well guess what? WINDOWS SUPPORTS THE SAME AMOUNT OF RAM UNDER PAE SINCE THAT IS THE PAE LIMIT! Since Linux runs on essentially the same damn hardware as Windows and since PAE is PAE, THERE IS NO DIFFERENCE.”

    There is a BIG difference as it does not work IN VISTA!!!! Also, you contradict yourself in the following:

    “There is no difference between Linux, Mac OS and Windows in this regard. 32 bit platform has PHYSICAL LIMITS.

    There is a difference as PAE is not supported in Vista. Check the charts yourself.

    So there you have it, a 36 bit virtual os running in a 32 bit kernel. So what if it works in XP!!! can you get it in Vista? WOW you get a downgrade.

    This ugly hack works fine in Linux! Maybe MS should copy it if they can not get it in Vista.

    So now you have helped all understand that a 32 bit OS can in fact address more than 4GB. Try and comprehend sixlime..

  43. Yet again. Like I said you prove me right. That it has nothing to do with the os like you contested. 32 bit kernal 4 gig of ram without pae. Stop changing the subject.

  44. Vista came installed on my notebook. I am unable to download my SpyWare program. Is there a reason?

  45. I have Window Vista 32 recently got a DELL Laptop having 1GB rAM and 120GB Hdisk but found to be very slow and i am planning to go for the XP rather.

  46. Okay so If I read this right I’m screwed? Here is the system I put together yesterday:
    Core 2 Duo 2.4
    Nforce 680i SLI Motherboard
    4GB DDR2 Memory 6400
    2x 8800 GTX 768 MB in SLI configuration
    2x 500 GB HDs in Raid 0

    So pretty much when I check my ram it says I have 2302 available in vista, when Bios reports over 4GB. Is that extra 2GB just going to waste then? Should I return the 2 1GB sticks to the store? This is a little confusing to me, as I never had this problem with XP. Is it possible this will ever be fixed? Thats kinda a let down, it seems like the more memory my Videocards have the less my system has, ands my total video card memory adds up to over 1400MB! (1.4GB).

    I saw an option on my motherboard to SLI my memory, I never heard of it, but I need special memory to do so, would it be worth it for me to do so?

  47. Not to double post as well, but is it worth it for to do upgrade to 64 bit then? What are the downfalls? Will I still be hit with the same limitations? I have a few days left to return parts to the store if I have to and I want to make an informed decision.

  48. Explain to me the reason for having on-baord RAM on a video card when Windows is going to try and use it anyway?

    Doesn’t make sense for someone, like me, with an 8800GTX 768MB video card.

    I have 2GB RAM installed at the moment. Windows and BIOS recognize 2048MB. No impact or “subtraction” of RAM due to video card. If the statements here were true, wouldn’t my Windows XP PC only “address” 1280MB of RAM?

    This is why high-end PC’s have high-end video cards and not on-board cards that “share” system memory. The system memory and video card memory are completely independant.

    Problems people experience are usually due to system board restrictions (try BIOS updates).

    I’m getting an additional 2GB to add to my PC and will test just to satisfy my curosity.

  49. Yes, I’d also like to know if XP 64 bit version also treats the same 4 gig ram the same way, I just bought 2 more gigs of corsair 8500c 1066 mhz, not cheap, and only see 3.144 gigs of my total 4 gigs under XP 32 bit professional..If I upgrade to the 64 bit version will it treat the same 4 gigs the same? I understand that I can yank those 2 gigs out and purchase 2 2 gig sticks and would be fine, with 6 gigs total at that point, but didn’t want to spend anymore money at the moment, and was hoping that someone would know how 64 bit would see the 4 gigs.

  50. I recently built a PC that has 4GB of RAM and it’s running Vista 64bit Ultimate. Vista shows 4GB of RAM.

    However there is a physical limit to 32-bit apps running on Vista 64 bit. which is roughly 2GB. It is possible to over ride this.

    Graphic Cards that actually go into a AGP/PCIe slot do not take up system RAM. They have their own onboard RAM.

    I’m a Computer Science Grad and I really don’t like when people go nuts over bad information.

    Get Vista 64-bit and get the patch if you have more than 3gb of RAM to access all of your RAM. It’s worth it for the future.

  51. I just bought a new pc with 4gb ram and vista32 home premium OEM and a 8800GTX videocard.
    Updated all drivers.

    My system can only see 3.3 Gb ram.
    When I run a game like battlefield or counterstrike, I get crashes to desktop and BSOD’s.

    When I remove 2 memory modules, my systems sees 2 GB ram and every games runs smooth.

    What is going on here ?

  52. Simply put, Vista, like XP, Linux variants, etc. DOES support PAE. However, an application MUST EXPLICITLY USE PAE to see more than 4 GB of RAM, that is to say, it must do the swapping work. The OS is incapable of doing this, as it has no way of knowing what can be swapped and what cannot in any given application. the key here is the word swapped, not paged in the proper sense.

    For those of you who go back to the days of Quarterdeck DesqView or IBM TopView (MS-DOS 3, mid 80′s) we had the EXACT same dileema back then. Then the Phar-LAP DOS Extender was created, and we could WRITE an app to use up to 16 mb (yes, megabytes) or RAM but we had to do in the application code.

    This situation in any 32-bit Intel OS is exactly the same. The difference between the Mac, Linux and Win32 is that the application developers and compiler writers write differently for these OS environments. There are few applications in the Win32 environment that are written and compiled for PAE simply because the need is not there. The DB apps are the ones that are typically written to support PAE, and SQL Server and the enterprise version of MySQL are PAE-enabled.

    The apps that we write for a living, for all 3 OS environments, are frequently PAE enabled, thus my own experience with this very issue. We’ve been writing with extenders since the 80′s.

  53. “applications have to be written specifically to take advantage of PAE”

    The program itself is not aware of the actual memory size. All the memory management and allocation of the PAE memory is handled by the memory manager independently of the programs that run.

  54. I had 1.5GB of ram before today. I added a 1GB chip today. BIOS detects 2.5GB, Vista Ultimate (32bit) only detects 1.5

    This is well below the 4gb/3gb issue detailed here. I should be able to see 2.5GB in Vista.

    AMD AthlonXP 2500+
    ASUS A7n8X-x
    2.5GB DDR PC3200 400MHZ
    Vista Ultimate 32bit

  55. Just recieved my new alienware area 51-7500, vista home premium wi 4 gb of ram, only 2.7 is in use, I imagine because of the geforce 8800 ultra hogging over a gig of it, is there no way around this I dont really want t o buy a whole new operating system

  56. Dear friends

    I am new in this, but defenedly i need to ask. I have the same issues on memory structure. From the start, I check the inestability on vista on this matter, no argue on this.

    I continue using it since i buy the windows.

    I am building a new computer for games. This is the confix so far.

    Intel Core 2 Duo 2.66 4mb 1333.
    EVGA Nforce 680i SLI Motherboard
    4GB DDR2 Memory (pending on speed and latancy)
    2 EVGA 8800GTS 320MB Superclocked
    1 X 250 GB HD SATA (pending on the configuration)
    Antec 800 Power Supply (the new one)

    The question is, I buy the vista 64x ulmate for this config

  57. “However, an application MUST EXPLICITLY USE PAE to see more than 4 GB of RAM, that is to say, it must do the swapping work. ”

    But the point is…
    If you DONT have PAE, then the 4 GB (minus reserved kernel address space) are shared by all the programs which are running, which leaves in general less than your 4 GB, especially on a bloated OS.

    If you have PAE, your program will enjoy the full address space afforded by your OS (2 GB or 3 GB), WITHOUT SWAPPING A SINGLE BIT.

    Not to mention, if you have PAE and 8+ GB, you can have 4 programs running happily and the same time, each of them using like 2 GB. Which is what you want when you have a quad-core for instance.

  58. im running Vista x86 and I currently got 2gb of memory and I wana go higher but would it just be better to just up to 3 gb and not to 4 so it doesnt take any away and I dont waist any money ??

    mail me back

  59. Hey, can anyone straighten me out! I have a new laptop running Vista Ultimate. Came with 2GB RAM. I installed 4GB using two 2GB sticks but windows only sees 3GB. I have reinstalled one of the orig 1GB sticks and windows still sees 3GBs. Here’s the question. Does it do any good to leave all 4GBs installed? Or should I save a 100 bucks and just use one 2GB plus one 1GB?

  60. Basically:

    If you have a 32-bit system:
    -expect not to see all 4 gigs.
    -expect you’ll see 4gigs MINUS at minimum your video ram

    Yes your video card may have its own physical ram, but it still can shared memory addresses with your physical ram.

  61. I ran into this issue a long time ago.

    I’m dissappointed that microsoft did not make such a stronger stand support of X64. Vista premium should be mostly X64, as most users who can run Vista should have X64 compatible hardware by now.

    By making their primary focus on 32bit, weakened support for X64 native drivers, and apps –> less compatibility, stuck with peripherals you could use under 32bit but NOT X64.

    So those with 4GB installed or more dont expect happiness when you goto X64. I’m on X64 now and yes I see all 4GB, and it works great as long as I dont need any application, peripherals that is further rendered unless. Therefore you’ll be at a crossroad. Go X64 for more addressable memory, or stay in 32bit, have less memory to use, but have more software/driver/peripheral compatibility. one of them will have to be traded off.

    If you’re using microsoft’s finger print reader for example, there is no X64 drivers, only Vista 32bit. Many vendors will support 32bit, and have not endorse 64bit Vista yet.

    I wonder if those Mac users on the other fence has issues with 64bit MacOSX. Jump to macosx? Lose even more software compatiiblity.

    this trade off sux. I know for a fact, 64 bit will HAVE to come sooner or later. 32bit has already max out in addressable memory on Windows. And more and more users are installing 4GB and more.

    I was at CompUSA earlier this year and I ask for a 64Bit copy of Vista and they say they dont have any… and that 32bit will last for a while and you dont need 64bit really. Well dont think they realize we’ll atleast need it for more ram, if anything else. with these new games and apps 2GB doesnt cut it.

  62. 8GB Vista Ult 32 Bit = 2GB in Vista Ult 32..

    I will say this, no matter what get’s installed. this thing is non-stop heart pounding amd fun.

  63. All Your Problems Is Micro-Fuck’n-Soft. I’m Runing MAC Pro With 4 GB Memory Installed 4*1 GB And It Detects Them All, When I Installed Windows By running Boot CAMP It Detects Only 3.1 GB of RAM Even In a MAC !!!!!!!!!!!!!!!!!!

    Fuck You Microsoft.

  64. I Everybody, just a simple note to share my own experience.
    I have a Q6600 4GB and an ATI HD2600PRO (512Mb).
    With this config i have effectively 3326 Mb availlable.

    This confirm explanation of the Author that i thanks particularly as i have wonder for a while where was my remaining memory used for.


  65. So if I have 2 gigs and a 32-bit platfom/OS, I can see the full 2gigs in Windows. Upgrading to 4 gigs, I only see 3.5 gigs because the rest is being used for other hardware (video card, etc).. Does this mean my video performance is now better :)??

  66. turning off aero? will that help in increasing memory stats?
    just a thought… no time/patience to try it out thought…

  67. 32 bit Windows.


    4GB is a waste of money in 32bit. If windows cant see it than it wont use it. The 4th GB is a waste.


    Note: 2x1GB+2x512MB = 3GB Dual Channel.

    • winxp 32 bits with 4Gb -> no exactly a waste, because if your video card is not discrete (but integrate), it can have plenty room to take on that 4th gb, so some cheap graphics chips in your notebook for example could catch up to 1 gb (normally 700 kb aprox ) for dedicated video memory.
      win 32 bits is designed to go UP TO 3.3 Gb at maximum even if you have 4, 6, 8 or wahetever your motherboard could support.
      of course dillema is only for 4Gb users, for 6GB, 8gb etc, the logic smart way is windows 64 bits or linux 64 bits.

      • What you seem to not understand is 32 bit HAS A 2GB LIMIT CAP! sure it can address more but it will only utilise 2GB of whatever you have anything more then 2gb is a waste of money! IF YOU WANT TO ACTUALY USE OVER 2GB YOU NEED A 64 BIT OS.

          • Yes 4Gb of address space but only 2GB usable as RAM. The other 2GB of space is for video cards,sound cards and other devices.
            You can read the limits at!

          • To Bubba, it’s 4GB address space minus space used by graphics cards and other adapters. If they happen to consume exactly 2GB, then it leaves 2GB for the OS. Often, they consume much less than 2GB. If they consume 750MB, as they do on my laptop, then it leaves 3.25GB for the OS.

  68. 4GB (4096MB) on Q6600 with nVidia GeForce 8600GT (512MB vidRam)
    32bit Vista reports 3326MB available
    64bit Vista reports 4092MB available

    In other words – 32bit is dead, long live 64 bit (at least until 128bit systems start to come) :)

  69. I have Vista Home Premium with AMD Dual Core 2.6ghz and Kingston 3gb 800mhz RAM. With stock video card Windows says I have 3006mb RAM. With a GeForce FX 5200 (256mb) video card it says 3070mb however windows rates my system less (and it performs worse) with the GeForce installed…
    As of now I’m going to just use the standard video card, I dont game or anything…

  70. Just one question.

    I can see why vista 32 bit will see less than 4gb that is installed, that makes sense.

    But why do we not see the same thing if we install just 2Gb. So only having 0.8 Gb avalible after the video card etc have taken what they need?

  71. Interesting then why 2003 32 bit server can recognize 4 GB of RAM without any problems and 32bit 2003 server R2 – 64GB?

    Looks like an artificial limit. And it has nothing to do with total address space, Window’s don’t address all of the physical memory directly. Instead smaller physical segments are being mapped as needed into address spaces of programs. And each program gets its own address space. So total memory can be much bigger then then addressing capability. Remember Extended/Expended memory of 286? It’s similar.

  72. I have Vista Home Premium 64X installed with 4GB of RAM in the Bios but only 3.5GB showing in Vista. Same thing happens with the 32 bit.

  73. On my laptop I have intel x3100 graphics. It uses shared memory for graphics. If I install 4GB I will benefit because it WILL be using my RAM from the MOBO instead of just mapping address space to the physical ram on a graphics card, right?

  74. I have the same problem, ive got a e6850 and 4gb of ram but there is only 2.5gb available. Ive got two 8800gt’s superclocked so in total 1gb of video memory and additional programs which confirms the explnation, kinda frustrating cause u wanna use all 4gb for some serious gaming. I hope microsoft will solve this with an update

  75. I have 4GB of physical RAM, windows vista shows only 3326MB. Does it really help if I have 4GB or should I just install 3GB memory? I just bought the additional 2GB memory (had 2GB before) and wondering if I should exchange for a 1GB one. Thanks.

  76. So I filled up my 4 slots to get 4gigs of memory with 1gig per slot. I should have bought 2gig sticks and filled up the machine with 8gigs total then I would not have to worry about the addressing issue? Or would I now be punished for having too much memory?

  77. Hello, i hav bought 8 gig ram DDR2 667MHZ not bad, its running on windows xp x32 bit its show only 3.5 gig weird but im downloading windows xp x64 bit, vista will be next i only got x32 bit in all version of vista, but on my bios of xp its show 8 gig memory weird lol …..cya take care be back soon

  78. I installed 4GB of memory on my low cost ACER 5220 laptop…all the memory is available…..start up is faster..but some start up programs are at the same speed……vista is shit!

  79. I just bought a new HP 9000t series media machine. I asked for the max memory of 4GB fastest memory available. This is a $170 upgrade. Vista 32bit only shows 3 GB of memory installed and 2.4GB available to the OS.

    Was it a waste of time to upgrade to 4GB?
    Should I send it back and get Vista 64bit or go back down to 3GB of memory?


  80. I just can add my sadness to all of you!!!! i have same situation:
    Vista 32bit, I added ram for a total of 4gb: bios ok, cpu-z ok, but vista only see available 3326mb! I have tried every possible tips, change the boot.ini, /PAE /3GB…nothing…after read hundreds and hundreds forums seems the solution is only one! install Vista 64bit, also if in many forums there are people that have same issue with vista 64bit and this make me worry!!!

  81. THIS IS WHY I BELIEVE your not affected if you have 2 GIGS OF RAM….

    I just read this whole entire thing, i’m not an expert but something just clicked in my mind half way down this post..

    I also have 2 gigs of ram in my laptop and I can see all 2 gigs in bios AND vista 32 bit… So my question was also “how come I don’t see 2 gigs minus my video memory in vista?”

    The answer? I believe… not 100% is this:

    Vista 32 bit is limited by uh.. 4 gigs of “space”. If you have have 512 mb of video memory and 2 gigs of memory on your system, you wont see a difference since .. 2 gigs + 512 of video memory only equals up to about 3.5 gigs, not pass the 4 gigs of “space” limit.

    However if you have 1 gigs of video memory.. and then 4 gigs of system memory.. you should only see “around” 3 gigs in vista since the video took up 1 gig of this “4 gig space” which leaves 3 gigs for the system memory to chew up.. but.. you physically bought and installed 4 gigs of system memory which can only fit into a 3 gig avaiable space left.. so that’s why it only shows up as 3 gigs.

    Hmm if I undersatnd it correctly use this formula to determine if you WILL or WILL NOT lose money on extra system ram installed…

    4 – (video memory) – (system installed memory) = POSITIVE number equals how much system memory you can still add to make it worth while, NEGATIVE number would result in how much you’ll lose from your system instlaled memory that vista will display.

    So.. lets say 1/2 gig of video memory (512 mb), 3 gigs of system installed memory would be…

    4 – (.5) – (3) = .5 amount of system memory you can still upgrade before it becomes useless in vista 32 bit and vista will DISPLAY the FULL 3 gigs of system installed memory.. the ram sticks.

    However.. lets say you have 1.5 gigs of video memory, and 3 gigs of system installed memory.. that would end up with..:

    4 – (1.5) – (3) = -0.5 Approx NEGATIVE half gig of ram. So out of that 3 gigs you installed in your system, subtract 1/2 gig and you’ll end up with 2.5 gig shown in vista approx.

    Lets try one more.. 1 gig of video memory… 4 gigs of system installed memory would be:

    4 – (1) – (4) = -1 NEGATIVE 1 gig taken out of that total 4 gigs.. so approx 3 gigs will be shown

    Oh wait wait one more..

    1 gig video memory and 3 gig system memory

    4 – (1) – (3) = 0 So.. technically.. you should only lose a tad if anything.. you filled up all the 4 gig of “space” with your video and system ram.. so you should be in the “ideal” “maxed out” position where.. installing any more system ram will just be useless i think..

    Someone correct me if i’m wrong :)

  82. Just a thought here. Video memory shouldn’t allocate system address spaces since it’s not visible to system. Anyone trying fiddling with AGP Memory size ?

  83. You are exactly right, Vista 32-bit can only assign 4 billion memory addresses roughly. The easiest way to figure it out is to 4 Gig then subtract the amount of vid ram you have. This is the total amount of ram that you can add and have Vista 32 use. So if you have 128 mb graphics card, you may want to go ahead and use 4 gb of ram. If you have a 512 mb card, you probably should use 3.5 gb of ram. What ever amount you have, expect a little less since other devices will need some of those memory addresses.

    That said if you have a 512 mb vid card and 2 gb of ram then you will be just fine. All of your ram will show up just as you expect since it only will be using 2.5 billion memory addresses.

    As for the people having trouble with memory upgrades reading properly in their bios, check the documentation on both your ram and your mobo. I’ve had a mobo that could only read half of a dual stick in the second slot. I’ve also had a mobo that would read the sticks in the first two slots as the same (smaller) size if they were different. You may be having a similar issue. It is at least worth the ten minutes of reading you will have to do to check it out.

  84. Hi there to all and i have a very good puzzle for you?
    I started off with 2 x 1gb of ddr2 @ 533mhz and my bios showed all 2gb of it and vista basic also showed the same, i then went out and bought a 2gb stick @ 667mhz and this showed in bios as 2gb and vista aswell, i then tried the 2gb and a 1gb and bios showed 3gb @ 533mhz and vista also showed this but my main question is why when i bought yet another 2gb stick @ 667mhz and placed this along side my other 2gb stick that my bios only shows 2.5gb @ 667mhz and vista showed the same?

  85. Very good Larry Wu, you all should know that your memory is THERE, being addressed the same whether it shows available or not, Vista can use up to 4gig and 4gig Ready boost, 8gb total, unless you have more than one physical processor, if you have a smaller amount of ram, buy yourself a good 4gig thumb drive, startup times are considerably faster and all i/o that won’t be written to disk is processed through the Ready boost, speeding up everything else because there is more ram available for the processes that will be written to disk. So you know I have 4gig in Vista X64, with SLI enabled, it shows I have 2.5 gig available, Kinda like Wezley there. One gig of video memory, so Larry’s formula doesn’t seem to be quite right. If a Ready Boost drive is in the USB port on startup, I suddenly have 3gig available WTF? I thought this was a nonissue for X64, but apparrently not. Oh well, I don’t care that much, this thing screams as it is.

  86. 32 bit Linux with PAE doesn’t require applications be specifically written to take advantage of it. Processes are limited to a maximum of 3GB of RAM EACH. I don’t know why Tony is bagging on 32 bit Linux with PAE anyway. You can get the 64 bit version for exactly the same price as the 32 bit version– Free! And, most of the applications included with the system are 64 bit as well.

  87. I have the same problem with the memory. I have an ASUS M2N-E SLI, AMD AM2 6400, 2 XFX GeForce 8500 w/512MB running SLI and 4 GB ram. My Bios sees the RAM but Vista Home Premium only shows me 2GB. What can I do to at least increase the ram?

  88. PAE!!! Shades of x86 flat and paged address spaces! Somebody screamed…IT CAME FROM THE 80′s! What’s old is new again. Yeehaw! ;^]

    I just bummed that my just recently bought laptop was installed with Vista 32-bit, at that! My OS sayeth 3004MB and yer worthy of no more. Go 64-bit and be happy YOU FOOL, Bill G. is telling me.

    But is it true that, for a pittance, I can do an upgrade to 64-bit after the fact within a certain time limit?

  89. i need 845 gvsr graphics driver for windows vista, i can’t get 32 bit, so plz kindly help me for this problem

  90. i just upgraded from 3->4GB in my notebook running 32bit vista. i gained ~230MB addressable ram. my windows experience for memory operations/second jumped from 4.9->5.9, my free ram per task manager, from ~15 to ~1000. i’m not sure how it will affect operation yet, but it’s the right direction as far as i’m concerned. if it helps keep IE from crashing, i’ll be happy.

  91. Plz can you give me the name of the game (any ) which uses
    RAM more than or equal to 2GB….

  92. I call BS! I upgraded an old Dell running 32bit XP to 4GB and the OS only shows 3GB. I removed 1GB and the OS still shows 3GB! LOL

    Can anybody justify/explain a 1GB overhead by adding 1GB? Again, I call BS. A couple megs, OK. A whole GB, yeah right.

  93. i have 6GB DDR2-800 phisycal memory but in BIOS i saw that i have only 5 an in Windoes Vista Ultimate i have only 3

    if someone know hoe i can ‘solve’ this problem please help

    ps: pls mail me the answer

  94. Hey WL

    If you reread the article above (its probably been updated since you wrote your question) you will see that it has got nothing to do with overhead. its because that there is only 4GB adressable memory space to memory, PCI, video card mem ect.

    so you identified that your computer uses abut 1 GB of adresses to everything other than memory. adding even 20 GB extra vill do nothing for you with a 32bit operating system

  95. i just sat down and read all the post before me and i am trying to understand why windows wont see all my RAM. i am running vista 32 bit and 64 bit both home premium on dual boot. i have 4 x 1 gig sticks of ddr 3200 with nvidia 512mb PCIe video. my problem is that both 32 and 64 bit windows only recognizes 2943mb. from what alot of people say the 64 bit should be recognizing all 4096mb, but it doesnt. like i said before it only recognizes 2943mb. now if i am thinking correctly the problem is my motherboard. becuase if the board was seeing all the ram, then the two different versions of windows which suposedly max out at different amounts would be showing different amounts, right? if anyone can help me it would be greatly appreciated.

  96. BIG FESH,

    What amount does your BIOS show? If you BIOS shows all 4GB, then I don’t know why Vista 64 isn’t showing all 4GB.

    It’s fun seeing kb and sixlime go at it. The funny thing is that sixlime is saying that the sky is blue, and kb is arguing with him that the clouds are white.

    The fact is they’re both right, but kb’s argument that apps don’t have to be specially written to take advantage of the PAE switch in Linux is only partially true – they have to be written to take advantage of Linux period… :)

  97. I read all these comment and I am surpised what you guys are seeing. Anyway, in my case everything worked as expected. So here is the details: I bought two computers:

    1. HP a6057c
    2. HP m8277c

    I added 2 Gig for each machine. So now each machine has 4 Gig of RAM.

    When looking at the memory in vista, it showed 3.2 of RAM allocated. So I reformatted each one and re-instaleld vista ultimate this time. Now both computers show the full 4 Gigs in Vista and these machines now are solid fast like a rocket.

    So in Vista Ultimate you should see the full 4 Gig Max and should not see less.

  98. what happens it i uninstall intel extreme graphics and why do i have 16 bit instead of 32 bit

  99. does anyone know how to change how much memory is being used on the graphics card. i was told i could change how much it uses but i cant figure it out.Please Help

  100. Reading this is funny to me. I have vista Bussiness 32bit. I HAD 1 gig of ram that showed up as .99 gig in system properties. I then bought 2 matching 1 gig sticks for a TOTAL of 2 gig. low and behold 2 gig of ram showes in bios AND vista. What seems to be the diffrence between my Toshiba A105-s4547 and your guys pc’s? Also my Dell XPS400 has 3 reads 3!

    Please respond maybe i can dig deeper into my pc and help solve memory probs

  101. I recently built a new system (yesterday)

    Q6600 2.4ghz (soon to be OC’d)
    4GB of crucial ballistix (4x1gb)
    9800 GX2

    I can only address exactly 3 gig of my RAM when in vista 32bit :( seems the GX2 is stealing a gig of addressing space, ah well it still kicks ass =D

  102. got an HP pavilion a1120n windows xp media center, installed 4Gb and it only shows up as 3.12GB, 32 bit system

  103. Just to add to the statistics:
    1. I have an hp Pavilion dv6000 laptop family
    2. RAM detected before sp1 was 3 GB, after sp1 now its 4 GB
    3. Nvidia GeForce dedicated memory of 128 MB and it took 1278 MB of RAM from my 4 GB so my total video RAM now is 1406 MB
    4. It seems my video card is automatically adjusting the amount of RAM to take by a certain percentage.

  104. Man, some people are still asking why they dont get there full 4 gigs in there system. Read the posts ( debate between slimlime and kb is helpful) and you will know why. But i doubt those people wiill read this, they would have read the other posts then -_-

  105. Tried a few different combinations of operating systems and memory. from windows me-win vista ultimate 64 bit. had the same problem with not showing my actual memory installed as decribed, untill I downloaded and installed service pack one for windows vista, new service pack went from showing that i had 3.2 gigs of ram, to the four gigs I had installed. (vista ultimate 32bit). Just for the fun of it i tried Vista 64 Bit-Dell xps 420,Quad core 6600,8800gt nivida,yada yada, No problem,ran smooth and found drivers to work also used sandisk 4gig flashdrive for ready boost.After reading all of the hype was suprised not to have been more challenging! LOL

  106. 32 bit vista, 4GB RAM – all visible to BIOS but only 2.75GB when in windows

    i dont get the same limitation in vista 64

  107. What is wrong with you people? This issue has been beaten to death! It’s been explained in the article above, at numerous other websites & at If you’re running a 32-bit OS, it cannot address more than 4GB RAM. And if you install 4GB, a portion of it MUST be used by other hardware. The BIOS *should* report the full amount, but Windows will report somewhere between 3 – 3.5GB depending on your hardware…in some cases it may actually report lower than 3GB. Regardless, all the formatting & reinstalling in the world is NOT gonna change things! If you wanna make full use of your 4GB RAM, install a 64-bit OS. Then you can post back about how you’re having driver issues & how much WinXP x64 & Vista 64 suck…LOL! Enjoy…..

  108. Well, WTF, I’m guessing the issue with these people is the seemingly arbitrary assignment of a 4G limit on the RAM…

    If the limitation was really due to being 32bit instead of 64bit, why isn’t the HD space limited to 4G also? Of course they’re different things, but shouldn’t it be possible to update the OS and hardware to recognize more than 3G + 1G for the filesystem? Why can’t they do it like a HD and just say “Ok, here’s 1G for the filesystem and everything over that is looked at as available RAM…”

    Alot of us gamers want the extra ram to make our games go *zoom*, but don’t want the 64bit version to make our games go *poof*….

  109. Well Friends,

    Just the same like others.. my vista shows 3.062 GB of Ram,
    btw i use Tohsiba Portege Laptop M600-341

  110. Hi,
    Support fully 4GB physical memory under Desktop 32 bit OS is impossible, Some 32 bit Server OS can support over 4GB when used PAE. But you still need to check your HW condition if support or not?
    I summaried the key condition for desktop support over 4GB physical memory as below.
    1. Desktop CPU: Support 36bit address (After P6 are all support)
    2. Desktop Chipset: Chipset FSB also need to support 36bit address (after 965)
    3. OS: Please use 64 bit OS.
    4. May BIOS support re-map
    Otherwise, in desktop it’s impossible to see over 4GB phiscal memory…

  111. The issue with vista not seeing more than 3.5 of your 4gb of ram is over. Im assuming atthis pont most if not all of you have the service pack 1 for vista. when you install this it will fix the issue of not seeing all of your ram. once i installed the service pack my vista business registered all 4gb of my ram. not that it really makes all that big of a difference. most of the everyday users dont really run anything that requires more than 2gb anyways. unless you are an animator or CAD designer

  112. The poster above is correct, Vista “reports” 4GB. But that is the only change, it’s a visual one. It doesn’t mean that it can now address the 4GB, in the backend, you are still limited by what the article talks about, and what some of the commenters have mentioned.

    (And to answer some of the PAE questions, I believe it works such that Windows will automatically page/virtually address 3GB of RAM per application/thread, but no application can address MORE than this, unless they take advantage of special PAE APIs, which usually only the big database apps do.)

  113. Vista 32 Ultimate. 4x1GB DDR2 800Mhz reported as 4GB of which 3.581GB available to Windows. Gigabyte GA-965P-S3, DualCore Intel Core 2 Duo E6420, 256 MB nVIDIA GeForce 7300 GT.

  114. This is wrong Vista 32 bit will recognize up to 5GB of Memory at least. I have a screen shot of the system resources that proves it. While I’m also using vista 32 bit I only recognize 2.75GB While I have 4 installed. My boss’s Vista 32 machine recognizes all 5GB he has installed in his machine. My boss and I have not figured out why he recognizes all 5 and I can only recognize 2.75

  115. install vista sp1 to recognize up to at least 5GB of Memory. After my last post of only recongnizing 2.75 GB of memory, I installed SP1 with no problems and now see all 4 GB of memory.

  116. Wow! Some people here cannot read, I recommend you step away from the computer before you hurt / electrocute yourself!

  117. FYI, Vista SP1 only reports the installed RAM. Keywords are “reports” and “installed”.

    Just because it reports installed RAM, doesnt mean that it uses all of it.

    Most likely, it still uses 2.75GB of RAM, Joey.

    I understand why Vista sees 3-3.5GB of RAM when 4GB is installed.
    What I dont understand is, why doesnt Vista see 1-1.5GB of RAM when 2GB is installed??

    People are talking about how 32bit cannot address more than 4GB. Key phrase here is”more than”…. We dont care about MORE THAN 4GB at the moment. Let us talk about trying to use 4GB without going 64bit.

    If that was true, then why does Vista only use 3-3.5GB?

  118. Also, my computer is installed with 4GB of RAM, with 32bit Vista Home Premium.
    My onboard graphics is set to 256MB of RAM.
    However, only 3GB is available for Vista to use… instead of 3.8GB

    (which is what it should be, according to my understanding of this article)

  119. I had 4 GB ram with 2x8600GTxxx 256MB SLI The first install of Vista 32 bit only showed 2.8GB RAM avail, so I waited a few months, reformatted, did all of the updates and now I show the full 4 GB. Maybe it was just a needed update. XP will also show the full amount of RAM installed regardless of how much it is scavenging off the system.

  120. Here’s a strange one!

    A server with a Dual Core Opteron and 4GB of RAM in it is reported by Windows Server 2008 (32bit) as having 8GB of RAM!

  121. Hi

    I’m going buy a laptop. It has 4 GB of RAM and a 32-bit OS. But it also says that I will have 64-bit Computing.

    Does this mean my laptop supports a 64-bit OS, or does it mean I will have access to all of my 4 GB of RAM?

    • It Means That Your Processor Can Work With 64 Bit OS Editions , But Has A 32 Bit OS Currently Installed. This Is Common For Laptops.

  122. I got Intel Quad Core. With 4Gb Ram , 32bit Vista Ultimate , & its always shown 4gb Ram

  123. I built a system for a gent last year with 8GB installed, and vista sees all of it.

  124. “I understand why Vista sees 3-3.5GB of RAM when 4GB is installed.
    What I dont understand is, why doesnt Vista see 1-1.5GB of RAM when 2GB is installed??”

    Like what previous posts said (though a bit unclear): there is a direct mapping between “address space” and “physical memory”; note that those are 2 different things! A 32 bit system can only address up to approx 4GB of physical RAM (or whatever it is that needs to be addressed by the system).

    As an example to your question, 2GB + BIOS/Video/Other stuff that needs a memory address will fit nicely inside a 32 bit address space. That means the OS has enough addresses to access all of your 2GB memory.

    On the other hand, 4GB + BIOS/Video/Others can’t be all addressed by a 32 bit system. The system would allocate addresses first to BIOS/Video/Other system resources. Whatever is left in the address space is used to map to the physical RAM, hence giving you less that your 4GB.

    A real world analogy here would be a town with a finite number of addresses as mandated by the local post office. Let’s say the post office declared that there would only be 100 addresses available for this town. Of course, the post office, police station, fire station, mayor’s office, etc. would need to have their own address, leaving say 85 addresses available to the public. If there were only 85 houses, then all 100 addresses would have been allocated and that would be fine. But if there were 105 houses, 20 houses would not have their own address, and mail won’t be able to reach them.

    If you have a 32 bit OS and it reports that it is “seeing” 4GB of RAM, it doesn’t mean that it can address or “use” all of it.

    PAE has been explained by some of the earlier posts and I won’t go into detail on that.

    • Vista Actually Sees The Full 4GB , However Depending On The Ram Slot Type it may Only Be Able To Use 3.5 GB.

  125. 32 bit 2gb ram is as good as it gets!
    you can only fully use 2 now get over it, if you want to make use of over 2gb get a 64 bit os. jesus christ!!!

    • 32 Bit Editions Can Work With A Max Of 4GB. However , In Older OS Editions (Like XP) , Your Computer Can’t Use A 4GB Ram Due To The Diffrent PIN Type. All Vista Editions Can Use 4GB Apart From Vista Starter , With A Max Of 3.2 GB

  126. I am considering buying a new PC. I want maximum RAM, so should I get a 64-bit OS? From what I’ve read on here, I should opt for Linux…

    Any of you techno poofters got any advice?

    • To Be Honest , The Best Thing Is To Get Either A Mac Or PC , Linux Doesn’t Really Support RAM Over 1.5 GB.

  127. well, I am running two identical machines, both have 775 setups, one has a 2.4 e1600 and I am running Windows 7 ultimate 32 bit, I have 4 gigs of dual ram- it shows 4gigs ram but only 3 gigs usable. the other one is an e7500 cpu @2.9, with 4 gigs of dual ram, and it shows it is using and accepting the 4 gigs, it has vista 32 bit on it, bith have 1 gig nvidia pci express cards and both machines are given a 5.0 rating in the index.

    • The Most Likely Reason For This Is That Your Ram Slot Is Burnt , However You Must Make Sure That Your Computer Supports That RAM Type

  128. Its all very simple:

    32bit Operating systems -
    lots of hardware requires memory address space (video cards, pci cards bios etc). 32bit systems have a maximum of 4GB memory address space.
    if you have 4GB of ram installed it should show up as 4GB in bios. If it only shows up as 3GB in windows then 1GB of address space is used by hardware devices.

    if you have 4GB of ram installed it should show up as 4GB in bios. If it only shows up as 2.5GB in windows then 1.5GB of address space is used by hardware devices. etc.

    64bit operating systems have 128GB of memory address space, so you will always see the full ram amount as available in windows (unless you have 128GB of ram installed, unlikely!!).

    if you don’t see all of your installed ram in bios there can be 1 of several reasons for this:

    1. You may be using ram modules that your motherboard does not support.

    2. you may have exceeded the maximum amount of ram your motherboard can support.

    3. you may have faulty memory modules.

    in all cases if your bios does not recognise the amount of ram you have installed check the motherboard documentation first.

  129. They probably had difference amounts because of hardware allocation or reserved/shared memory with the integrated graphics adapter.

  130. I understand, this is a Microsoft Windows topic, but as a couple of people have mentioned this, so I decided to create potential flame-bait by giving my own user experience. Current Macs are completely 64-bit, and will even run PowerPC-based applications.

    I moved from Windows to the Mac almost accidentally, as I needed multiple operating systems to run my software development company. I used the Mac just for some minor graphics development and compiling / testing applications. Linux was always ‘too much’, in that, I respected its capability and architecture, but I really wanted an operating system to use immediately with no configuration consideration.

    Essentially, I wanted a good end-user experience. Despite my development background, I didn’t see why I should have to play with the operating system, so Linux could never fit my home and work user experience. Windows always seemed ‘amateur’ in comparison, but simple, which I wanted.

    Eventually, I started to really warm to the Mac OS, and considered what I used Windows for. I realised I could move to the Mac and not lose out. My life is on the cloud – calendar, e-mail, contacts, etc., and so all I needed were good applications to synchronise with those and with my phone. I needed a good development environment as well – I was using a mixture of Microsoft and open source development tools, depending on purpose, and this was costing a lot of licensing on top of the operating system. I found that the Mac OS had a superior, and free, development environment, called Xcode, and although it took some getting used to, just like the OS, I found myself much more productive once I was running. The e-mail client was better than Outlook has even dreamed of being, as was the whole integration with the cloud, and my Nokia phone. I even ignored Microsoft Office for the Mac and moved to Now our documents are all ODF-based and work perfectly well when corresponding with our Microsoft Office-using associates.

    So I’ve been using Macs for years now. I’ve bought quite a few, my extended family have all migrated and have no regrets, colleagues have moved over, and even my Microsoft-loving developer friends use them at home. As for the compatibility issue – I still need to develop on multiple operating systems, and I still like to use particular software intended for Windows and Linux. So I use VMware Fusion on the Mac. The integration of Windows into a virtualized environment is superb and allows me to do everything I need quickly. Ironically, 64-bit Windows 7 runs faster on my Mac in a virtualized environment (with 2GiB assigned), compared to running natively on my clients new developer computers (with 4GiB installed). I now have over 10 operating systems running on my Mac for my development company, and wouldn’t swap my base Mac for any other operating system.

    Getting rid of BIOS was a dream too, and although Windows 7 has some semi-decent UNIX compatibility and is also now capable of disposing of the BIOS, no PC hardware manufacturer seems to care.

    This is completely my experience, and those of the people around me, and I couldn’t say this would work for everyone, but I would heartily recommend considering it.

    • There Isnt Really A Diffrence In The Way A MAC Works To A PC. There Is Still 32 And 64 Bit Editions , So In Windows Computers It Really Depends What Your OS Is And Who You Buy It From.

  131. Isn’t system memory limited by what the motherboard can handle but not the OS, because Vista REQUIRES 2GB to run properly your saying Vista is limited to 3GB do that is only 1GB wiggle space and what about gaming, for gaming 3GB is nothing to run on, I guess no one would even bother running Vista for gaming because Vista adds to the requirements of games up like maybe XP 1G ram to 2G ram and Intel P4 3.0GHz to Intel P4 3.2 to 3.4GHz!
    Anyway I don’t like Vista I would honestly choose XP over it any day.
    Ok everybody that’s my opinion.

    • Vista requires 512MB of ram, not 2GB. The OS itself generally uses less than 1GB, no matter how much you have, so 2GB is fine for most people, and 3GB leaves plenty of room for even memory-intensive apps.

      Anyway, I recommend people use 64-bit Windows 7 over Vista and XP nowadays, anyway. It’s definitely better for gaming.

    • It’s NOT Limeted By The Motherboard Itself , It’s The RAM Slot That Has It’s Limits.Your RAM May Be Producing 2GB , But your RAM slot can only handle 1GB Therefore Making Your Computer Run At 2GB speeds. OS Editions Won’t Change it , You Just Need To Get A New Chipset.

  132. Hi!
    Can any one explain the issue regarding more than 4gb RAM, 64bit Vista Ultimate, NVidia Chipset and Intel Core 2 Quad CPU.
    I have a MSI P6N SLI Motherboard (NVidia Nforce 650i SLI Chipset) with 6gb DDR2 800 RAM, Core2 Quad Q6600 CPU, 2x GeForce 8600GT in SLI Mode. 32bit Vista ultimate works fine with my PC, but every time I try to install a 64 bit windows vista ultimate, a BSOD with STOP Error appears. This does not happen though if the RAM is reduced to 3 GB. Strangest of all, when I tried installing Windows 7 in this same configuration, there was no such problem.

    • In Order To Actually Use 64 Bit OS Editions , You need a processor capable of running 64 Bit OS Editions. Some Manufacturers (Especially Laptop Manufacturers) Will Put In A 64 Bit Processor And Install A 32 Bit OS. Basically , Get A New Processor.

  133. To Bhaskar Bhadra:
    In order for 64 bit operating system work properly the computer requires 64 bit processor(s). How 64 bits can be processed by a 32 bit processor simultaneously? In a 64 bit processor, there are 64 inward channels and thus the processing happens faster. In 32 bit processors the inward connections for data processing is ofcourse 32. So 64 bit operating system will not generate the optimum result.

    • Acer Aspire w/Vista Home Premium 32 bit install, Control Panel & My Computer show 4Gb, BelArc Advisor & Everest show 3Gb

  134. I have vista home premium.
    3 GB of RAM
    my system control panel shows 2.9GB

    I am thinking that Windows 7 would be a better performance boost.

    • Windows 7 is faster than Vista, but unless you upgrade to 64-bit Windows 7, it won’t change the amount of memory available. Reclaiming that last 0.1 GB of memory wouldn’t make a difference, anyway.

  135. Technically, Computers With A 2GB Ram Chipset Are Capable Of Using 2.3 GB (Max) Becuase Of The Processor’s In-Built Ram. Unfortuneately, When An External Ram Is Installed (RAM Chipset) Windows By Default Stops Using The .3 GB Of Ram Inside the Processor. Stupid , Eh?

    Also , Computers That CLAIM To Have 3.5 GB Ram (Usually 32 Bit OS Editions) Are Usually Caused Due To RAM Chipset Limits Being Below 2GB (If 4GB Capable Installed). Therefore It’s Not Windows’ Fault , It’s Your Manufacturers.

  136. hi!
    windows vista home premium
    4 GB installed RAM
    system info says it’s 4.00 GB.
    task manager says it’s 3 GB,
    dell software says it’s 3.00 GB, usable(2.99 GB)
    windows 7 says it’s 3.00 GB.
    i say: what the fuck! nobody other than me cares!

  137. After a clean Install of Vista 32 bit on my PC

    config –
    CPU – Intel Core 2 quad
    RAM – 8 GB
    MB – Intel DG33FB
    Disk – 1 TB * 1
    Disk – 120 GB * 1

    My Vista detects 8GB RAM after install SP3.

    • Vista 32 will show the amount of ram you have physically after SP3, but can not actually use it. Check your task manager.

  138. My base-score is 5.7 and I am shown a max of 5.00Gb for my RAM even though I have 12 GB in my machine. So that kinda blows the max of 3.00 for vista out of the water.

  139. I have a vista 32 with 4 gb ram at first it only showed up as 2 gb, but after service pack 2 I see all 4 gb and I think it runs really good

    Other people are always surprised at how fast my computer is and when I use other computers I get frustrated at how slow they are.

    I was going to bump it up to 8gb because I do allot of 3d art for games and want the faster render times but if it can only allocate 3.5gb I’ll wait till I get a new PC.

  140. I have asus, m2n32 sli deluxe 64 X2 dual core 4200+2.21 ghz. Prosessor! 6 gb ram, i see all 6! Strange!! And 32 bit vista home premium.

  141. Well I built a render farm with 2 amd 4 core processors, 8 gb of ram and 3 1 gb video cards. shows all 8 gb of ram on win vista ultimate black 32 bit edition.

  142. I have an intel board dh55hc, I3-core processor, vga radeon hd 5830, 500 gb hard drive and DDR3 2 x 2 gb = 4 gb, I use windows vista ultimate 32 bit,
    My question:
    1. whether my device is suitable for the existing system …?
    2. why I only read the memory 3317 MB on the Windows system …??

    my cpu devices support up 16 gb DDR3

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