I'd like to report the same problem. I picked up a new 'puter last weekend. It's a HP Pavillion Athlon 64 3700 with an nvidia 6200PCI turbocache 256. Specs here:
I put in the hardrive from the old PC which had a 32 bit Fedora Core 5. That froze when using anything 3D. So then I installed the 64 bit version of FC5 and same problem. I used the livna nvidia drivers.
I didnt really pay attention to the freezing at first as my old machine also crashed a lot using nvidia drivers but after several reboots seemed to stay stable for days on end. But this one is just freezing and the cursor doesnt even move.
Not sure what other info would be required.