Just tried switching to DX11, and lowered my max fps to 30, with a 30% render scale, and I got a full 5 man run of freehold done. Seems to have worked, but this isn't really a way to play. Hopefully it was DX12 and I can play with higher settings. My CPU isn't that bad, 4690k i5 3.5, so I'm hoping its not the problem.