My daughter bought a gtx980 from her friends game design business and when she got it it looks like new, not a speck of dust on it. I put it in my pc and my pc and fired up bf1 and it shut down, it did this twice. I updated the drivers although I didn't think I really needed to as I'm running a 970. I managed to play a full 30odd minute round of BF1 operations without an issue. Shut it down to go food shopping and I get a call from son to tell me my pc was hard locked. Could it be my 550w evga psu isn't strong enough or is the card most likely a lemon? Edit....I'm running a stock clocked 2600k, 4x4gb 1866 ram, 1 hdd, 1 2.5"ssd, 1 M2 ssd, a sound card and about 5 fans and an H80i.
I have a gold rated Silverstone 650w PSU that would shut down when drawing around 500w from the wall ( I've got one of those cheap wattmeters) If your PSU is older it may not deliver the power it did when new.
It's not too old, about 3 years I think. . It did both shut down twice then locked up twice. I played for 3 hrs on bf1 this evening to test it out and it was fine, even seems to be a much sharper image than on my 970.
I've found unigine heaven to be a pretty reliable gaming stress test. Maybe give it a few hours of that and see how it behaves? Perhaps with something CPU intensive at the same time. PSU would still be my No1 culprit tbh especially as the card is now behaving.