I've never used XP but I know when I had 2K pro on it was a fair amount slower with the same hardware, not on RC sims mind you cause I didn't have any at the time, but in general on games. That said, 2K is wonderfully stable compared to the other MS junk (if I can get the extra hard drive loaded in the family PC I'll be trying to get G2 running in Wine on Linux, cause it doesn't seem to like my P3-450 with no 3D card that I've got Linux on now when it comes to running higher end 3d Games at least)