Re: Challenge NV
For some time, I've been wondering about these dozens of problems people are having. For me everything has just been working perfectly after I sold my Radeon-cards away and bought a bunch of GeForces. Even driver version 6111 is now working perfectly, no performance loss anymore (which was my only problem ever with nVidia and simply reinstalling the drivers corrected it).
I must come to the conclusion that you must be running some hardware, that is not entirely compatible with nVidia- or some other drivers. I would start finding the problem from there.