My guess is a problem with your RAM. I was having the same issue with my new build but the blue screen had a message about bad memory. My problem was solved by removing the RAM and reinstalling it. I guess I must have had a bad connection when I first put it in. So my suggestion is to reseat your memory and run memtes and see what happens. Maybe having the game constantly utilizing your RAM during a game has something to do with it not causing any problems during a game. I'm wondering if all the fans in a computer constantly spinning might cause enough "micro" vibrations, that we don't really notice, to the system which in turn might cause connections inside to loosen up a little bit. Maybe not enough to completely dislodge a cable or screw but enough to cause one or two pins to have a bad connection. Of course this is just a theory of been thinking about lately especially since I built my new system and realized that there's 7 fans all together inside the rig; 1 CPU cooler fan, 1 fan on the PSU, 3 case fans and 2 fans on the GPU. And I still have room for 2 more fans in the case if I want them. That's a lot of moving parts in my opinion.