AMD GPU drivers crashing at random in VM

[Stevieboy]

Running the most recent unRaid. Machine is asrock z370 extreme, 8700 (non-K), 24gb 3200, 1080ti, rx480 8gb, 512gb Samsung Evo.
I've got the machine split down the middle into two gaming VMs (my wife really likes the idea of another gaming pc for our boys, so I grabbed the first GPU I could find and doubled up my current machine), 3 cores, 6 threads, 10 GB, 200gb, latest Win 10, latest Nvidia driver, older AMD driver that works (18.9.3).

Afterburner & Rivatuner tell me that i'm not maxing out my CPU capacity.

Both install fine (including the buggering around to install the AMD driver), all my games go in fine (Forza4, Fallout 76, Subnautica, various Lego, Portal).

BUT if the Nvidia system is under load, the AMD system will have a driver crash, the game video will freeze but I can still alt-tab out of the game, end the process and still have control of the VM.
If the Nvidia system is off, the AMD side runs fine.
And Fallout76 will crash on both systems at random, so that's working as usual.

I know AMD drivers are flaky AF (the second monitor will have a frozen mid-shutdown image even once the AMD VM is totally shut down).
Is there a trick I've missed with the rx480 or do I just have to wait till the new year and pick up a 1660?

 

Edit - thank you for the move mod, what were the odds of me putting my first post in the wrong place, eh?

Edited December 23, 2019 by Stevieboy
I'm a muppet