Ive been on the evga forums and found a few users with the same issue. Game runs fine for a little, then frames drop, screens go blank (audio continues ) and either have to reset you computer or the game comes back up. So far the few of us have in common out GPUs are all 570s, Some SC and some HD SC models.
What I have done to ensure my system is 100%:
First of all, all other games i have work fine. MW2, COD4, Farcry2 and a ton more.
Checked my PSU for correct voltages
Gave my gpu a litte more voltage while downclocking it to regular 570 speeds (i own a 570 SC)
Reinstalled the game (and steam on a new user account)
Tested with the latest driver and the beta driver
Installed firmware update for my card.
Made sure temps were down.
Still I am having the same issues, its not at an exact moment in the game. Usually at random. When watching my graphs right before my screens turn off, gpu load takes a spike upward, then plunges to 0% load, as well as fan speed, fan tachometer, memory speed, clock etc. Everything on the graphs plunge. surely this is not health for any computer component. I have currently stopped playing to ensure no damage will be done to my hardware, but this is just another issue I felt needed to be addressed.
Its a shame there isnt more support for the PC version.