Geesh you're all ovbiously n00b's, the trick is as with any quake 3 arena engine based game is use the console. Then type r_DisplayRefresh "x", followed by com_maxfps "x". Then finally type vid_restart.(Where x is the desired refresh rate).
The first command manually sets the refresh rate, the second command then sets the maximum frames your video card will display. The third just reloads the current map, prefabs etc and applys the settings.
Quake 3 Engine normally overides any little programs such as Powerstrip, RivaTuner and others so this is the best way to fix it.
If you have any other queries with quake engine based games (there's hundreds of them now), just email me at
cbuttery@optusnet.com.au and i would be glad to help.