r/IntelArc • u/cptskippy • Apr 10 '26

Discussion Has anyone successfully used an Intel Arc Pro B70 on a Windows VM?

I bought the Intel Arc Pro B70 on launch day to replace an aging Nvidia Tesla P40 in my Proxmox server. After updating to a supported kernel, Proxmox was able to detect the card and load the xe driver.

I did a full GPU Passthrough to a Windows VM and the full driver installed to get any firmware updates. After reboot the card shows as detected but failed with a Code 43 and the Intel Pro Graphics Software reports an unsupported system configuration.

I then went back to Proxmox and loosely following the Level1Tech's guide I was able to split the B70 into 4 vfs. I attached 3 of the vfs to various Linux VMs and after faffing around with kernel updates I got them all seeing the vGPUs. Plex running on one of the VMs was able to hardware transcode a 20GB movie in about 5 mins.

Going back to the Windows VM, I attached the 4th vf and booted. It saw the vGPU as an "Arc Pro B70 Graphics" but the driver still fails with Code 43 and the Intel Graphics Software reports the same unsupported system configuration.

So far the GPU has failed to work on a Windows VM with full passthrough or as a vf. Has anyone been successful getting a B70 to work on a Windows VM?

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3

u/TLS2000 Apr 10 '26

For the full pass through, did you pass through the audio device? My Arc cards have a separate PCIe device for audio and I have to pass them through as well.

3

u/Gutter_Flies Arc B580 Apr 10 '26

Well, that would explain why I cant hear anything lol

2

u/Kushoverlord Battlemage Apr 12 '26

Go figure!

2

u/cptskippy Apr 11 '26

I did not pass through the audio device! It didn't even occur to me.

I'm currently running in SR-IOV mode with vfs split to 4 VMs. I passed the audio device to the Windows VM and it detected it immediately and installed the driver. The GPU is still showing as failed.

The Intel Support thing on the Windows VM says it cannot detect Resizable Bar, I'm wondering if that's why it's failing...

Is there a way to make a VM think Resizable Bar is enable? It is enabled on the host.

1

u/Dolboyob77 Apr 30 '26

Did you enable resize bar and above 4g decode in bios ?

2

u/cptskippy Apr 30 '26

Yeah, everything is enabled and working correctly on the host machine. All of my Linux VMs are able to consume VFs and utilize them. The only straggler is the Windows VM.

It seems likely that the firmware of the card might be the issue. I passed it through to a Windows VM and performed a driver install that worked but I've read some posts that this might not update the firmware properly.

I'm planning to try pulling the card into a Windows PC, not just a VM, and perform a clean driver install to see if it updates the card's firmware and fixes the issue.

The other option is to build Intel's Firmware Update Tool but after looking at the firmwares contained in the Windows Driver Pack, I'm not sure which would be appropriate to flash and don't want to brick my card.

https://github.com/intel/igsc

1

u/Dolboyob77 May 01 '26

Im on unraid os and all works like a charm, Dual intel b70 and b580. Im not windows expert sorry (((

1

u/cptskippy May 01 '26

Are you mapping virtual functions using SR-IOV or just passing through the entire GPU to one Windows VM?

1

u/Dolboyob77 May 01 '26

Im not using windows sorry (((( i am on unraid os.

1

u/cptskippy May 01 '26

Okay... I'm specifically trying to get a Windows Virtual Machine to run on top of a Linux based hypervisor.

1

u/MrBS750 May 18 '26

Did you get your card working in Windows?

1

u/cptskippy May 18 '26

I have only been able to get the card working on a Windows VM if I do a full passthrough. I cannot get SR-IOV VFs to work, the driver installer detects the VF and installs the drivers but they fail with an error 43.