Hello guys, I used vfio with 2 gpus passed through for years, now on a Z390+9900K. I’m evaluating to upgrade to AM5 platform, but I need help on the motherboard choice.
I’m considering these three:
Asus Prime X670-P (price ~€250)
Asrock X670 Steel Legend (price ~€320)
MSI Pro X670-P (price ~€280)
I need to use iGpu as primary gpu for Linux host, and two gpus for two vm. I don’t need performance on the second gpu, it’s more important to not take pcie lanes from the first one… So I’m ok with the second slot connected to the chipset, if the GT710 I’ll put there is in its own mmio group.
I need at least 4 sata ports, and I don’t need to passthrough usb controllers or nvme.
Any suggest?
I have X670E steel legend, and I chose this board specifically for the additional PCIe slot to fit in 2 dGPU like you. X670E steel legend made sure that PCIe 5 slot lane is not reduced with other NVMe or PCIe devices.
Looking back, I would think twice though about going AM5. Compared to my previous Intel build, it took a lot of extra work to get passthrough working. It’s been a year since the initial release, but 4 DMIM and DDR5 EXPO is still poorly supported on AM5. I also planned to pass the iGPU to one of my VM, but so far have never managed to achieve the goal, nor finding a success case on the internet.
Thank you. I don’t need to passthrough the iGpu, as it’s for the host graphics. I prefer AM5 for future upgrades and I don’t know what to do with crestmont ecores from Intel, as they are weaker than my actual CPU cores…
In theory, IOMMU groups is not that big of a concern on AM5 mobo. Most, if not all, have hardware ACS support to split every PCI device into a dedicated IOMMU group. But in reality, I couldn’t even enable IOMMU or even CSM with another brand B650 mobo.
For intel P core E core, at least it can be harnessed with careful CPU pinning. I have 3 monitors at home, so the DP and HDMI slot came with iGPU is not enough, hence the idea of iGPU passthrough. But right now I’m at the edge of scrapping the idea to pass the iGPU.
If you’ve decided to go with AM5, be prepared for a lot of troubleshooting.
What kind of troubleshooting? If the GPUs are in their own groups, and I don’t need to pass iGPU/USB/nvme what can go wrong?
Exactly what I thought in the beginning. But no, I knew nothing what I was going into.
amdgpu.sg_display=0 kernel parameter will be your friend.
I also disabled re-size BAR, frame buffer, and supplied the dGPU with vBIOS to get the pass through going.
And I was using nvidia dGPU. If you go with AMD dGPU, there’s the glorious resetting bug.
reset bug, as I know, depends from the GPU, not the platform. My 6600XT has not a reset bug, so It should reset on AM5 too…
Vbios thing instead could be quite annoying, as now I don’t need to put a vbios on the Radeon nor on the GeForce, and I can see boot screen on both. I’m ok with passing a vbios but “not so much” with not be able to see boot screens on vm’s…