This has been happening for awhile for me as well although slightly different. About once an hour, the computer shuts off. No blue screen or errors. My PSU is 850W with Crossfire'd 7900s. PSU is I believe, 4 years old, give or take a few months. Strangely, I started having this issue when I moved my computer desk to another side of the room. Probably has nothing to do with anything. Also this only happens with XIV and no other games (at least that I tested in my Steam library.) I kinda wanna explore every option before having to blow $120+ on a new PSU.