2nd GPU cannot find enough free resources in Windows 10 VM

[twixxals]

I’m trying to pass-through two GPUs to a Windows 10 VM on UnRaid 6.9.2.

Here are my VM settings:

 

Everything works EXCEPT Windows refuses to use the second GPU. Device manager gives the error message: “This device cannot find enough free resources that it can use (Code 12).”

 

Only the primary GPU is usable in the VM. Both GPUs work when set to the primary. Neither work as a secondary with the same error message as above.

 

Running bare metal Windows 10 on the same machine works flawlessly.

 

I’m loving UnRaid so far, but this is a major roadblock for me to finish my setup.

Any advice on how to fix this would be greatly appreciated!