Windows Gaming & GPU passthrough (4k 120hz)

[eskyyer]

I’m running truenas scale for 2 months now, and I got plenty of processing (AMD Ryzen 9 5950X + 128GB RAM) left unused on my server.

I was wondering if I could transfer my nvidia RTX 3090 to my server and have a VM run windows for gaming.

Here comes the newb Qs:

• Who takes over the screen connected to the GPU, truenas or the VM with the GPU passthrough assigned?
• With GPU passthrough, will the windows VM take full, or close to full advantage of the GPU performance + connected screen specs, such as its resolution and refresh rate?

Thanks in advance!

 

[Migsi]

To quickly answer your questions:

1. When you pass through a whole GPU it is dedicated to the VM, so you will see Windows booting and so on. At this stage, TrueNAS won't be able to do anything with the GPU.
2. Due to the minimalistic configuration approach IX-Systems decided to take, you probably won't get bare metal performance, as lots of tweaks can't be done, or at least are very hard to perform to the KVM config. Depending on your setup you could probably be fine with it though. If you have the chance to try it, do so and see if its good enough for you. Don't forget to perform reference benchmarks on your bare metal gaming rig.

Note that you must have installed at least two GPUs into your TrueNAS box, as it ridiculously TrueNAS won't allow you to isolate the only GPU in the system (please vote up this issue). You can work around this limitation by following the mentioned steps on the issue and the linked writeup in the comments over there.

 

[eskyyer]

Thanks for the info @Migsi, indeed, I might experiment a bit with it, but so far decided to go a different route, I'll be defaulting my main OS to proxmox, and from here, run truenas on a VM; I'm finding truenas VM support to be too limited (I'm sure it'll keep on improving) on customization options.

 

[Dreamer]

To quickly answer your questions:

1. When you pass through a whole GPU it is dedicated to the VM, so you will see Windows booting and so on. At this stage, TrueNAS won't be able to do anything with the GPU.
2. Due to the minimalistic configuration approach IX-Systems decided to take, you probably won't get bare metal performance, as lots of tweaks can't be done, or at least are very hard to perform to the KVM config. Depending on your setup you could probably be fine with it though. If you have the chance to try it, do so and see if its good enough for you. Don't forget to perform reference benchmarks on your bare metal gaming rig.

Note that you must have installed at least two GPUs into your TrueNAS box, as it ridiculously TrueNAS won't allow you to isolate the only GPU in the system (please vote up this issue). You can work around this limitation by following the mentioned steps on the issue and the linked writeup in the comments over there.

well it's a shame that you can't use passthrough but what if your CPU have an integrated GPU in it? i could then passthrough another GPU?

 

[farout]

If the GPUs end up in their own IOMMU groups, it might work. But with some hardware combinations it even doesnt work then.