What are the advantages and disadvantages of the two types of system? I know that 64bit allows more RAM then the 3-and-a-bit used by 32bit, but what other differences would you expect to see? I am particularly interested in Windows7. Thanks!
Perhaps have a look at these questions:
16-bit applications cannot run when the processor is in 64-bit mode.
Not really a showstopper for most people, I realize, but there are a few legacy 16-bit apps out there that some people still rely on. Ergo, running a 32-bit version of windows ensures that the 16-bit apps still run because the processor is not operating in 64-bit mode.
Alternatively, if 64-bit windows is a must, then the 16-bit app can be run in a Virtual Machine.
Aside from the main reason of supporting more then ~3.5 GB memory without "hacks", there are a number security and reliability things that a new architecture allowed (since you would have to ship new drivers and applications). Specifically (from KB 946765):
- Mandatory Hardware Based DEP (compared to weaker/slower software based DEP)
- Kernel Patch Gaurd which attempts to limit drivers to only use supported kernel interfaces (this is a big deal for reliability)
- Driver Signing, so you have a way to identify whose software is causing problems and potential block the signer of malicious code
You might like to listen to the recent RunAs Radio podcast Phil Peery On the Powers and Pitfalls of 64 Bit Operating Systems!, it is somewhat server orientated but I found it interesting.
Personally I run 64 bit Vista and Sever 2008 at home as well as a few 32 bit OSs, I had lots of problems with an ATI graphics card blue screening the Vista box but after replacing it with a Nvidia card it's all good now and I'm really glad to have 8G of ram on both machine. (especially with how cheap it is now!).
I have only found one device (a barcode readers RS232 adaptor) where the 64 bit drivers are not available which is a pain but then I just use it in a VM.
I'll just copy the reply I gave on a similar topic. It might help you.
This should help you, even though it is written for Windows Vista. Windows Vista 64-bit - Is it worth the upgrade? This explains the following: benefits & limitations introduced by 64-bit, what to consider when installing the 64-bit version, benchmark results and user experience changes. All things here do apply to Windows 7 as well. I've been using the RC version of 7 for a few months and i confirm that's the case.
The PROS are... You have double the bandwidth across the CPU for every single clock cycle You have more memory that is accessable to the operating system You have the ability to speak to applications in 64 bit mode which can be a significant performance increase
The Cons are.. Insufficient device driver support across the board.
For 32 bit
PROS Good across the board device driver support
CONS SLOWER Less memory available to the OS