ByteBool

Afternoon, was hoping one of you fine folk could point me in the right direction.
 
Over the weekend I setup a Windows 10 Pro gaming vm.
I've passed through the gpu and thats all fine, but the issue I have is that I cannot change the res or refresh rate.
I can play games and all that no problem, but I'm stuck at 2560x1440 @ 30hz.
I've used the nvidea control panel to change to 3440x1440 @ 120Hz and works fine when I test it, but as soon as I try to apply the changes after the test, the screen will flicker, as though it's tried, but nothing changes, and the custom resolution is now greyed out.
 
I've also tried using CRU but the changes made there will only work within the bounds of the dummy DisplayPort (I don't have a monitor attached to the server). If I remove the dummy, I only get a black screen.
 
Nvidia control panel seems the way to go, as I can get the res to work when test, I just for the life of me cant get it to stick/apply.
 
Any other ideas?
 
 
UPDATE: I've managed to get nvidia custom resolution to 3440x1440 @ 30hz. The issue seems to be when I try go above 30hz.
When I try switch it to 60hz, it works when tested again, but when trying apply 60hz, it jumps right back to 30hz. Not sure what I'm doing wrong here...