Go down the nvidia route's the best advise. wont be going with AMD again until they can sort the many issues with their drivers out.
Nvidia have a TDR issue, which isn't dissimilar that has been effecting huge numbers of Nvidia users lately, the driver not responding problem and the equal version from Nvidia is almost always caused by system instability elsewhere. At this point in time there are almost certainly more critical bugs heavily effecting Nvidia users than AMD right now. Difference is Nvidia users tend to post problems on Nvidia's forums, where there are huge threads with many people having problems with the TDR thing, you just don't read about it a lot elsewhere.
Both companies have great drivers, all users will eventually experience problems no matter which side you like more, both companies have problems with big game releases and getting xfire/sli ready and working on time for a big launch. Anyone that thinks one side has problems and the other doesn't, is deluded.
The issue you have experienced may not be related to the graphics card at all.
After installing my ssd I experienced the same sort of problems and I traced the issue back to an incompatability problem between my drive and the Intel storage drivers (the drivers enable a power state unsupported by my drive), which could be fixed by either disabling write caching (but this could cause data loss on power failure) or by enabling hot swapping for the port the ssd is using in the motherboard bios, which is what I used and it immediately fixed my problems.
Hope this helps.
Yup, basic driver stopped responding stuff from Nvidia or AMD is almost always the driver simply being the FIRST thing to crash in an unstable system both because its the least stable and the most complex driver, which shouldn't be surprising.
You have system setup Y, its overclocked, and you add a new gpu, most people upgrade and there is a general trend that new cards in a similar bracket use more power than the last gen version. You've got higher power usage, often different driver, different types of power draw and different loads and people end up with a just marginally less stable system than before, but that can be the difference between driver crashing and not.
I've only ever got repeated driver did not respond situations directly after an upgrade and after bumping voltages marginally, or backing off an overclocking marginally each time it's disappeared.
This goes for AMD and Nvidia and 90% of them, mine include, are user error. Hell, when that kind of thing happens and maybe bios reset's itself or I have to change a voltage, I might have had a stable system and overclock for a year, and forgotten which voltage does what and what needs tweaking.
SSD's in particularly lately with apparently very "odd" Intel drivers, in which its suggested a lot of their features are buggy as crap and using loads of driver work arounds and constant new fixes which is smegging around with power states and causing loads of ssd's to be incompatible or buggy with it.