Hi,
Regarding what I suspect is the issue: instead of disabling PBO, you should check if there are settings to try and lower the operating parameters.
Did you test with a different SSD? You mentioned it froze at the loading screen.
Did you try testing with different RAM modules, other than the ones you are currently using?
Do you know how to create a bootable MemTest86 USB drive to test the memory directly?
Thanks.