I have an r7-1700 sitting in a box under my desk, I've had it for at least a year now, a friend side-graded away from AMD back to Intel and I got it cheap. I'd like to finally install it into a new system but I want to be able to play games in linux land and I know there has been huge improvements with Valve Proton, DXVK, Vulkan, Lutris etc... but if possible I'd like to be able to run a VM with Windows and give it direct access to the GPU and some of the CPU cores. This is possible right? You just need the right hardware and to enable some things in the UEFI?

My preferred mobo form factor is matx, but it's not a deal breaker if I have to go full size.

Do I also need a second GPU?
Any suggestions greatly welcome! TY.

Partial answer: Google linux vm pass through gpu for instructions how to use graphics directly from a VM. I had the same idea as you and found that it is possible without too much effort, but it seems that a GPU can have only one master: Either the OS running on the host, or the VM’s OS.

So yes, it looks like you need a separate GPU. Since my system is a laptop, adding a GPU is a bit difficult and I have never tried this out.