This is as far as I can get with the AMD kexts and the device ID added. They load but the frame buffer isn't loaded. I've tried loading all 7 frame buffers included in the X1000 kext with no luck. From the tests Gigamaxx did there seems to be more luck spoofing as Intel graphics there. More support may come from integrated Vega though, hard to tell.
as documented here it is a sample rate standard and i have also tested it and i can confirm that it works with my audigy rx at least, i have to test it with other cards