My friend and i have same systems, only he has 2000 AMD and i have 1200. He's getting 75 fps avarage on WinXP. I'm getting average of 85 fps. With playing rtcw. So it's oke for me
U can tweak Xfree very good especialy with quadro cards! Check this one: http://download.nvidia.com/XFree86_40/1.0-3123/README
Note to get the new 3123 drivers!