GPU crashing/potentially failing

[1940s Wigwam]

I recently bought a used EVGA GTX 1070 off ebay and installed it in my rig. Since then its displayed odd behavior in a few ways; it can continually perform without problems in some games/benchmarks, while crashing nearly instantly in others. Some notable (and repeatable) crashes have been in Gears 5 and Subnautica. The crashes themselves are a bit strange since the game will freeze, continue audibly running for about two seconds, and then the screen will flash a random color and all I can do is power down the pc and turn it back on. Interestingly there are no error messages to be found other than windows being incorrectly powered down after the crash.

 

Speccy: http://speccy.piriform.com/results/jBkyhjlKKtWU8YaMbv7hUgy

The PSU is a 500w 80+ Bronze that came with the prebuilt.