My OS is Mandrake 8.1. Maybe it'll be better in 8.2...
I'm assuming you haven't installed the drivers yet (so it's working without hardware acceleration): http://www.nvidia.com/view.asp?PAGE=LINUX http://www.linuxnewbie.org/nhf/intel/distros/mandrake/mdk_nvidia.html
(skip to halfway down the linuxnewbie page). You know when you have installed the drivers, since you get an Nvidia splashscreen when you frst boot up, or if you restart the X server with a ctrl+alt+backspace.
Enjoy! (I would add that many people have had no problems with these drivers, but I certainly have).
Ricardo