I'm having similar issues with my 680. When playing various games, I get a sudden black screen and often times, you can still hear the game playing through the audio, but you have no video. When this happens, it will either eventually come back to the game with a drastically reduced frame rate, or it bounces me back to desktop with a Windows message declaring the driver stopped responding and is restarting with reduced settings (which never seems to recover). Temps peaked at 77C, but are usually in the high 60s to low 70s. Also, the power supply is a just a few month's old Corsair 850W, so power shouldn't be an issue.
My card is a Superclocked card, but if I downclock it to stock non-Superclock speeds, I haven't been able to reproduce the problem. This is all with a clean Windows 7 install and using the DVI-D connector with no adapters.
Lastly, the card was tested in a second machine and the problem moved with it.
My system works great with my old 580 in it, so I have an RMA started for a new card. Hopefully the chances of getting two bad cards in a row are slim.
<message edited by rixhobbies on Friday, May 11, 2012 10:05 AM>