Speaking as a technician, you would be surprised at how one small setting or missing DLL can cause a rockin’ system to grind to a halt on certain programs. for example, your cpu has 2 different variances with one specifically stating that certain motherboards would require a BIOS update to use. But since you can load into the system period, that is likely not the issue. There are other nooks and crannies of the GPU or motherboard that may lead to some point, but there isn’t any open evidence that points to anything specific other than its having a hard time either reading or storing the data. So unless your psu is underpowered (which I doubt since a 970 likely requires a 6/8pin adapter just to boot, you have a faulty sata cable, or your hard drive is having random read issues (not the same as sequential read) then I’m at a loss.
Even if it takes 30minutes, if you can successfully load into the game and have successfully played a game with no issues, then your system has no problem playing it and its quite strange to say the least.
All that said, if you run a performance benchmark on your hard drive and everything passes then I’m out of checks for the moment.