well i was gonna run WAR, but that game has graphic issues so i probably wouldn't be able to tell the difference. I started it up though and i run a solid 30fps or so with fraps recording which is great since that's what i wanted for the most part.
The memory thing is rather depressing, i'm not gonna buy a 64 bit OS just to handle the extra memory so w/e I'll just have that in there anyways lol.
Ram+VideoRam< 3,5 Gig @x86 32bit OS
Don't ever touch XP 64 it's rly crap.
Never found anything that didn't run on Vista 64, met a lot of guys who weren't able to run stuff though (that I could run).
If you aren't good a figuring that kind of things out, you might have problems with it.