Which isn't bad, it within the 10K range. If the deviation were larger then you should be concerned.
I hope this is not normal. The only game i have tried is world of warcraft, and i get about 20fps in that game.
That may have something to do with your slow CPU, and also your settings versus his, as WOW is not really THAT VPU intensive.
My cousin have a x800 pro and he is getting around 80fps in world of warcraft.
Are you both at the same quality settings? Same type of maps with same number of people? What's his CPU? Likely it's something else that's an issue, there's little that would create that much of a difference. Maybe you have AA/AF enabled he doesn't?
Did you clean out the old drivers from your last card (or even better yet format) when you upgraded to the X850P?
My motherboard supports both 4x and 8x, and currently its set to 8x.
Won't make more than a statistical difference. It's something else that's the issue.