Motherboard Recommendations for i9 GPU Passthrough

We are planning on passing through 3 1080tis to 3 seperate qemu VMs in our lab and were planning on using an i9 processor and were looking for x299 motherboard recommendations. I know Wendell did a livestream where he did passthrough on an MSI motherboard, but he doesn’t say specifically which one. We have had problems with IOMMU groups in the past.

pretty much every x299 board has working IOMMU, so that’s not a huge issue, you can use any model you want that lets you put most/all the gpus on the CPU lanes instead of the pch

note that passing multiples of the same card complicates things, because of the way vfio-pci and qemu recognizes each device.

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Can you elaborate a bit on the vfio-pci and qemu issues, we don’t need to reserve any for the host. Would Zen or something else be a better option? We aren’t totally sold on what vm system we use, we just need the VM GPU passthrough density of multiple VMs with GPUs in one system.

VFIO-PCI id’s devices by part code, not by uniquely identifying info:

https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVMF#Using_vfio-pci

read this section, it explains the problem and describes some workarounds:

https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVMF#Using_identical_guest_and_host_GPUs