I've had an issue for a while now where my computer crashes to desktop (black screen and then desktop) within 2-10 minutes (usually around 3 minutes), whenever I'm running a graphics heavy application, like either OCCT, Furmark or a newer game on high settings. I can usually still hear the sounds from my game once I crash, but I have to completely restart the application to be able to see anything in it.
I started by checking temperatures, but they all seemed within reasonable limits, with the graphics card hitting about 70C on Furmark and my other components never going past 60C. I tried cleaning out my case and graphics card, which didn't seem to have that much dust for starters and although the temperatures lowered marginally, it made no difference otherwise.
My computer runs completely fine otherwise (except for one crash I had watching an 1080p youtube video) and I've run the OCCT GPU, PSU and Linpack tests without issues, the windows memory diagnostics tool and I've also tried updating drivers (my issues did not coincide with a driver update), then cleaning out all the drivers using AMDs driver cleaning utility and reinstalling them, to no avail.
I had a .Netframework 4.5.1 update recently before this started happening, but from what I've read around, no one seems to have gotten similar issues because of it and just to be safe, I did try a repair install of it anyways.
I've also tried unplugging everything from all the USB ports and then my graphics card took at least twice as long to crash. Changing the clock frequencies to stock or even as low as 20% below stock, had no significant effect.
From everything I've tried, I suspect that I either have a faulty graphics card or power supply, but I don't have anyone to switch components with and I have no clue as to what I should try next.
ASRock Z77 Pro4
Intel Core i5 3570K
Corsair 16GB RAM
Radeon 7970 Windforce 3x (R797OC-3GD)
Corsair GS600W 80+
Catalyst version 14.4
Windows 7 64 bit, SP1