So I have been having this problem pop up for a few weeks now. I upgraded from 2x stock speed Crossfire R9 270x's to a single GTX 1080 (EVGA FTW edition). I tried everything from reinstalling windows and the game, doing completely fresh driver installs, memtest and different power supplies to no avail. I was at my wits end last night until I saw a few people had mentioned how dx11 on this game hates overclocks, even factory OC's. So I dropped the core clock on my gpu back down to the stock speeds and have yet to crash.