CPU's, and windowsxp?

I have been back and forth many times from 2000 to xp, and I always run games faster on xp. I also get 1500 more points on 3dmark2001. I am wondering if anyone knows the exact reason why it is faster, and if it is the card being sped up, the CPU, or it just runs faster because of the programming of it? I mean if the game I want to play is heavily CPU dependant. Will it run it faster, because of the way xp effects the CPU, or maybe just the card will be faster, or both just because it runs faster the way its programmed? I need to know not just so I can switch back to xp for more speed, but also because I dont know if I want to switch cause I wll then need more RAM.

I heard it was some kernel.

Anyone know anything? Kind of need to know so I can install, or not.

Maybe cuss its justa newer OS, Some people actually think windows 2k is faster when running 3dmark2k1. I personally dont care if they think you can score more points in 2k1 with win2k, i like windows XP because its more effiecent and runs more smoothly

i think xp is probably probably uses the proccessor more efficiently. btw since when is more ram a bad thing?