Ok, a few things.
First is that Unity doesn't play well with some modifications. Under/Over-volting is one of these. Doesn't matter if you can run Futuremark and Prime95 at the same time without an issue, Unity will have a problem. Errors like this are often what you see. I have personally run into this playing with settings on my 6800 XT.
Second, you never once mentioned installing GPU drivers. After any Windows install/Update/Upgrade you absolutely must perform a clean installation. Those errors are a common effect when you are running on the "Microsoft Certified" drivers that get installed with these updates. You should absolutely perform a clean installation of GPU drivers downloaded from Nvidia. Can opt out of the GeForce bloatware while you're at it as well.
Third is that PSU. No offense to your purchase, but Corsair has had the highest rate of failure of any of the PSU's I have worked with over the past five years. I literally just replaced one of those a few months ago because it had failed for the third time and nearly baked my motherboard in the process. (It did roast one of the hard drives in my RAID configuration.) It could simply be that it is breaking under the strain.
This title in an unoptimized game in Alpha development. Even without that, it is more demanding on your core components than nearly any other program is. The Corsair before the last one was in a similar state. It would work just fine for benchmarking, overclocking, and could run just about anything. Run 7 Days and the system would crash. After intensive testing with benchmark and burn-in software not resulting in failure, but 7 Days crashing the system contently, I finally pulled it out and ran some tests on it with a meter. The 12v rail to the motherboard was failing under load.
This is actually a pretty common theme around here.