hi:
this is my config: i7 7700 + 16gb + rx5700xt shappire. Actually im running a "petite" unraid server with 5tb array and windows 10 vm. Thanks to spaceinvader's videos i learned that amd gpu needs q35 for drivers to load.
I launched the vm without any bios, because always crash/hang in boot, you can try without loading an extra bios file.
Im happy with the 5700 in windows, performs 95% well in comparative with native instalation.
the only "bad" thing... i didnt succed a worging catalina vm. Tried multiple forms... never boots... allways hangs before login screen.
hope i can help a little.
p.s. Sorry for my bad english.