Here is my current situation:
I have a GTX 560 Ti that has been installed on a Win8 machine for about a year and a half. It's been fine for most of that time, but the last month or two, I've been getting increasingly frequent freezes on my machine. I'm not necessarily doing anything intensive (it's often just idling on the desktop), and the PC freezes completely, requiring a forced reboot. When it comes back up, there's nothing. No error message, no pertinent log in event viewer, nothing. This behavior alone is enough to make me think video driver, but I've now had a couple of times where it pauses, recovers, and then flashes a handy notification bubble stating that the Nvidia kernel for driver xxxx has encountered an error and recovered.
Tried so far: I've updated the driver, both to most current release and beta, with no improvement. I've uninstalled the card and it's current driver (through Device Manager), run a registry clean, and reinstalled it; no change. I've monitored the temp during these crashes, and it's nowhere close to where heat would be a factor.
At this point, I don't know how to tell if this is still a driver issue or the card itself. I've never had any tearing or artifacting, but the freezes are becoming more regular. I don't have another video card readily available to swap in and test.