I have the exact issue on Win 7 64bit Ultimate.
I can play between 1 min and 1 hour before my screen freezes, artifacts of random color pixels appear, and I get a crash to desktop, however the game is still running and I have to force it to close via task manager.
I've had issues every since the game came out of beta.
Arma 3 is the only game I have issues in.
I also have an EVGA 580GTX
i7 920 at 3.2GHz
12GB GSkill DDR3
SSD
Win7 64Bit Ultimate
Several people seem to have the same issue with 500 series cards.