Problems with voltages (I think) AMD 290 and HD 7950


Oct 27, 2014
I'm on W7 64 with a 750w corsair psu, MSI 970 Gaming, 8gb 1600 ram, an 8320e, and an AMD R9 290 (xfx core).
I've never had problems with the card before, and a few weeks ago it started randomly black screening (sometimes during internet surfing, but almost always during a game, be it dota 2 or Barony.)
I've searched everywhere online and most people claim it's a voltage problem within the card, suggested switching drivers (which I've done a dozen over a couple years), using Afterburner to get more or less voltage, or stable volts at least, and downclocking and keeping a stable core/mem speed (disabling the energy saving throttles.)
None of this has worked.
I've also put in an older HD 7950, which fails to load at all. Both work in safe mode under the MS drivers, but in those cases nothing like DX is being utilized or putting it to load either.
Could this be a problem with my PSU? Why would both cards have issues? The 2 gpu power lines are on separate rails already. I've clean installed W7 to no avail.
Any help would be appreciated. I'm going to try a different psu and hopefully find an entire computer to test either card in.