How much RAM is supported in Windows XP

I'm running Windows XP (32-bit) on iMac Summer '07 model in Boot Camp, just incase that matters.

Thanks for the link, I'll looked at a few more websites as well. I've gathered that XP 32-bit has a 4GB Memory limit, and that hard drives, video cards and sound cards etc take up some of this memory. Only after they have used some of the memory, then whatever RAM you have will boost it up to the full 4GB. So
I'd end up with around 3-3.4 gig of main memory available for XP to use after everything else has used the memory.

Is this all right, If so then I will probably just buy 4GB RAM as I can make use of it on the Mac side, and will have to loose around 1GB on the Windows side. I don't want to have to update to 64-bit especially as only a few programs support it.

Thanks again, Mark.

Do you think that it is worth upgrading another 1GB or 2GB of RAM then, or only if I start running Snow Leopard in 64 bit and buy Windows 7 in 64-bit. To be honest I would rather stick with XP, it's a very solid operating system and not all my programs are available in 64 bit.

So I have to stick with Windows XP 32-bit due to compatitbility with some of my programs and HD capturing device. I would still like to upgrade RAM, should I get 1GB or 2GB? I don't mind buying 2GB and only using 1.5GB, as it is fairly cheap.

The problem is that I record PS3 Gameplay with a Hauppauge HD PVR, and it doesn't have a driver that works with Windows 7 64-bit.

And I do very intensive HD Capturing and Video editing in Sony Vegas, so I need all the CPU I can get, therefore I have to run in Boot Camp, can't use Parallels or anything like that.

Thanks, well I can't upgrade to 64 bit windows 7 due to incompatibility with hauppauge drivers, the only thing I can do to speed up my mac is to either upgrade the processor or graphics card (RAM isn't really an option now).