Lately while playing OpenGL games under Linux, my games have been freezing the system, complete with visual artifacts. It wasn't too bad until just recently, Ut2004 can't be played for more than a few minutes without it happening. I can play fs2_open a while longer, but it still freezes after awhile. I don't think it's my video card overheating or anything hardware related, because I can play games like F.E.A.R. and Half-Life 2 under windows for many many hours without any problems. Anybody have any ideas? My specs in case it helps:

AMD64 3000+
1024MB RAM
300GB SATA
40GB ATA
GeForce FX 5700
Generic DVD-ROM/CD-RW
Ubuntu 5.10 AMD64

Sounds like a drivers problem. Check what driver version you have, then go to nvidia, see if they have a newer one and install it. If you have absolutely the newest one, then maybe you could try to downgrade the driver version. Sometimes drivers can be buggy

Already did that. Tried new, old, 64-bit, 32-bit, still keeps happening.