I have been trying to get my unraid system to passthrough multiple VM's to multiple graphics cards with some success but still not quite working 100%. I have been able to get 1 card to pass through successfully but I cannot seem to get the VM passthrough to work with 2 cards (eventually 4). I have purchased a cheap 710 low profile GPU for $40 as was recommended because ryzen doesn't have integrated graphics and the POST seems to be eating 1 of the cards (slot 1) and won't give it up to the VM passthrough. Here's what I've tried:

 

a RX580 in slot 1 and another RX580 in slot 3 = cannot see GPU in slot 1, can assign gpu in slot 3

swapped RX580 in slot 1 with RX580 in slot 3 = cannot see GPU in slot 1, can assign gpu in slot 3

a RX580 in slot 2 and another RX580 in slot 4 = cannot see GPU in slot 2

a RX580 in slot 1 and 3 with a 710 in slot 4 = cannot see GPU in slot 1 but can see 710 and RX580 in slot 3 (closest I've gotten, but want to use the 2 580's)

710 in slot 1 with RX580 in slot 2 and 4 = can only see 1 RX580 (?!?!?!?)

 

CURRENT SPECS:

2x radeon RX580

1x nvidia 710

ROG ZENITH EXTREME x399 motherboard

Ryzen 1900x 8core Threadripper

 

DESIRED OUTCOME

I would really like to have 4 gpu's that I can use with VMs at the same time. I am trying to get 2 to function correctly first but cannot seem to get the hang of it. I don't want to have to rebuild the motherboard and CPU if possible. I think I just need to figure out how to properly assign these graphics cards. Any help would be greatly appreciated.

 

PS: I have watched the SpaceInvaders One videos and the linus videos and I'm still not getting what I'm missing.

Edited March 10, 20197 yr by littleman11186

I'm not familiar with your motherboard but the Asus Prime X470-PRO that I have has a BIOS option to allow you to specify which PCIe slot has the primary GPU installed. I'm not using an APU so I put a cheap Radeon HD 5450 in the bottom slot (x16 slot with x4 PCIe v. 2 lanes) and selected it in the BIOS then when I later added an RX 580 in the top slot (x16 slot with x16 PCIe v. 3 lanes) it was ignored and the BIOS and OS continued to use the card I had specified. It would be worth checking to see if your BIOS has a similar option.