I'm runnin vista on my brand new PC, specs are in the sig (I actually have 3GB of PC5400 DDR2 RAM now, dell screwed up 3 times with my order so they sent me an extra gig free) Works flawlessly. Worked pretty decent with 1GB too, but not really satisfactory. at 3GB, my RAM usage has NEVER gone over 30%, usually hovers around 20. Completely turned off the harddrive swap file, and runnin like a dream. I think it has something to do with the CPU (unless you tried Vista with onboard or a Radeon 9x00 or GeForce FX series or lower, which Aero is going to school you until you get a better one

). I've got a GeForce 8600GT. I use Vista because of DX10, its actually not all that bad, and the first set of DX10 benchies are horrible due to the bad drivers, mine works very well.