I'm having this issue for nearly two years now. It comes and goes for no reason.
I tested all my hardware and everything is working fine but still for no reason each time when i use gpu demanding software/games i get black screen (sometimes BSOD) for no reason. I tried all 3 GPUs that i own plus some other ones that i could get my hands on and still go the issue.
First i was getting BSOD pointing to outdated GPU drivers so i updated from 13.9 to 13.12 and that fixed one part of the issue after that i started getting error that points to what i managed to findout from Microsofts forums/support that it has something to do with Dx itself. Checked Event Viewer and everyhing i have there is issue with Kernel Power caused by hard restart after screen goes black.
Issue appeared every time i played Star Trek Online or Warframe and will stay for couple months before going back to normal.
I also tried both Win 7 and Win 8 still got it on both. Only OS that i didnt got it on was Linux.
Intel q9400 @ 2.6 Ghz
2x2gb Kingston HyperX DDR2
HIS HD6970 2GB Turbo and 2x Asus HD 4870 512MB
1000W Cooler Master Modular PSU
This system was never overclocked and all temps are normal CPU 32c Idle/ 60 - 70 HEAVY load (3D particle simulations FumeFx,Krakatoa,RealFlow), Gpu 35 - 45c idle/ 60 - 70 Load sometimes even less it depends on the game/software.
I want to sort this out before i get myself new rig for gaming/work so that i can pass this one to sis for her WoW no life sessions.