So, i was mining on my 5850 and gaming on my 5870. My monitor suddenly goes black, system locked up...i rebooted, thinking it was the 5850, which was damaged from my earlier bitcoin days, but it wasn't. The 5870 was the one that died.
Sure the room was hot, but the card was at stock, if not, then at 860/1200. And the fan was at 77% and i was playing Counter-Strike where GPU usage was like 16-20% tops. But, no matter what i did, even after a reboot the 5870's fan was just constantly at 100% probably indicating it's dead.
Thank god i still have warranty, but i have no idea IF they will even accept, it(no mention of mining ofc, just heat).