Thanks for attempting that . At least you have a new 980Ti on the bench to “test” ;D
Did you by chance get to look at my copy of dxdiag I posted? I was just going over it again and noticed some UE4 specific entries at the bottom of the file. Not sure if those are “normal” or helpful at all. I may try to setup a dual boot with Win7 on this machine to try and further narrow down the issue.