I've been having a similar problem.
Crashes to black screen while Far Cry 3 or Tomb Raider (sometimes audio continues/stutters, sometimes vanishes along with the display) which can only be "solved" with a cold reset.
My Nvidia drivers are up to date (347.88 installed - already completely uninstalled and reinstalled to test) and the games are using optimized settings as suggested by GeForce Experience.
I have not overclocked the card any further than the factory overclock; instead I've tried underclocking it (with Precision X) as suggested in this thread to see whether that fixed the problem (it didn't).
The card doesn't seem to be overheating. I used Precision X to set up a custom fan profile and aggresively cool the card as soon as it hits 60 degrees. Testing with FurMark and OC Scanner confirms that the fan profile is active (fan noise jumps suddenly when the card goes above 60 degrees); however, I never hear the fans get that loud in either game before the crashes occur.
I'm beginning to suspect that this card is a dud. It isn't performing as it should, despite not being pushed particularly hard.
I've just opened a support ticket. We'll see how EVGA responds.