I play in XP 64bit... works fine.... running 6800 GTs in SLI mode with 2gigs of ram and 2-150 gig raptors in raid0 configuration... I only had to replace my processor from Athlon64 3000+ to a dual core Opteron 175 becuase the processor couldn't keep up anymore... with the new opteron, everything is peachy again.... hopefully I won't need to replace my video cards anytime soon.