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

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 OpenOffice.org. 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.

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!!).

Note:
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.

Any of you techno poofters got any advice?

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.