This problem isn't limited to WoW, I get the exact same symptoms described here (abrupt performance degradation, restart resets everything) in Civilization IV and Red Alert 2. With Civilization it happens after only about 10 minutes of play, while Red Alert 2 can run for over an hour. If it's an issue with Nvidia drivers, a large range of them are affected as I'm using the 169 series OpenGL vendor string: NVIDIA Corporation OpenGL renderer string: GeForce 6800 GT/PCI/SSE2/3DNOW! OpenGL version string: 2.1.2 NVIDIA 169.12
