Hi all, venturing into multi GPU VM on Unraid and trying to dial in the motherboard we use, How is it possible to passthrough 2 (or more) GPU to a single Windows 11 Pro VM?

I am using EPYC 128 core with 2 x RTX 5090 (well I actually have 8 attached but let's start with 2) I have a single 5090 working perfectly right now.

Managed to workout the miniscule + symbol to add more GPU!

But I have a constant desktop moving from 1 gpu to another on every reboot, i.e I can use 1 display/GPU, reboot and then its on the other each time I cannot use the other GPU/display, any tips guys?

Has no one used dual GPU in a single VM?

6 hours ago, Richard RB said:

Has no one used dual GPU in a single VM?

i would say not too many as there is also no real benefit.

multi GPU support in Win is either a iGPU / dGPU setup, save energy (iGPU) and have Poer (dGPU) when needed.

and Crossfire, SLi, ... are "dead"

you may have to attach monitors to each VM (or atleast virtual ones) and then run into setup your Windows to prio somehow which one is 1, which one is 2, thats all i can think of right now. may rather look on windows help howto achive this.

It’s for 3D rendering, so yes I need as many as possible.

15 hours ago, Richard RB said:

It’s for 3D rendering, so yes I need as many as possible.

i wasnt aware there is a rendering software which makes use of this, but nice ;)

as mentioned, may rather search for Windows open issues on such a setup and about primary display "jump" on reboot if there is somehow a way to nail it down ...

On 9/26/2025 at 4:57 AM, Richard RB said:

Has no one used dual GPU in a single VM?

Not in Unraid, but I have run a few dual GPU VMs in Proxmox, which is also KVM based like Unraid.
It didn't move the primary gpu around, but I only ever SSH or VNC'd into that machine.

Is it possible you changed passthrough hardware , or physical hardware multiple times?
That would likely change device ordering