Proxmox with 2 GPUs, 1 on an x16 slot another on x4?

[fx9]

I have an old Asrock Fatality AB350 Gaming K4 Motherboard (latest Bios with Ryzen 5600x), the manual says the following:

PCIE1 (PCIe 2.0 x1 slot) is used for PCI Express x1 lane width cards.
PCIE2 (PCIe 3.0 x16 slot) is used for PCI Express x16 lane width graphics cards.*
PCIE3 (PCIe 2.0 x1 slot) is used for PCI Express x1 lane width cards.
PCIE4 (PCIe 3.0 x16 slot) is used for PCI Express x4 lane width graphics cards.**
PCIE5 (PCIe 2.0 x1 slot) is used for PCI Express x1 lane width cards.
PCIE6 (PCIe 2.0 x1 slot) is used for PCI Express x1 lane width cards.
* PCIE2 will downgrade to x8 mode when A-Series APU is installed.
** PCIE4 will downgrade to x2 mode when A-Series APU is installed.
** If M2_1 is occupied, PCIE4 will be disabled.

So If I decide to Pass though my GTX 1080 GPU to my Proxmox Windows VM (on the 16x slot) and another Intel Arc A380 to a Proxmox Ubuntu/RockyLinux VM install. Would the Arc card run at a maximum of 4x?

I'm trying to get a Proxmox environment up so I can virtualize my Linux development environment. Has anyone tried to pass through 2 GPUs to different VMs before in Proxmox?

 

[dbwillis]

I havent passed through with Prox yet, but going by the PCIe info, yeh, PCIe4 will be 4x max, unless you have a drive in M2_1
Isnt one of the GPU needed for the physical machine, or the board doesnt mind booting without a video card?

 

[fx9]

I figured I was gonna have it boot headless since everything is configured in a browser anyway right?

 

[cdabc123]

A pcie 3 x4 lane isn't a major bottleneck even on flagship card, should work fine.

I have multiple headless esxi rigs with lots of gpus passed through. I've only ever tried proxmox with one gpu a long time ago but I have to imagine you can pass-through whatever you want.

 

[dbwillis]

I was thinking the motherboard might complain when it doesnt have a video to output to on post, but if it saw a vid card, might lock onto that on bootup and not let it get passed thru ?

 

[cdabc123]

I was thinking the motherboard might complain when it doesnt have a video to output to on post, but if it saw a vid card, might lock onto that on bootup and not let it get passed thru ?

on esxi, it will set its main display on boot, then reroute it when the hypervisor gets to passthrough devices. I dont think it would be an issue

 

[Vengance_01]

I have an old Asrock Fatality AB350 Gaming K4 Motherboard (latest Bios with Ryzen 5600x), the manual says the following:



So If I decide to Pass though my GTX 1080 GPU to my Proxmox Windows VM (on the 16x slot) and another Intel Arc A380 to a Proxmox Ubuntu/RockyLinux VM install. Would the Arc card run at a maximum of 4x?

I'm trying to get a Proxmox environment up so I can virtualize my Linux development environment. Has anyone tried to pass through 2 GPUs to different VMs before in Proxmox?

Should be okay if both cards have decent Linux drivers. If I had an extra slot I would test for you. Currently passing a P400 to an LX container vs a full VM without issues for plex encoding.