Asus ROG Strix x570 E-Gaming faces issues when using the GPU on PCIe_x16-3 as the primary or host card.
Asus ROG Strix x570 E-Gaming faces issues when using the GPU on PCIe_x16-3 as the primary or host card.
Hello! I understand you might be in the wrong forum, but I’m not sure it’s the right place. To be honest, this issue doesn’t seem to be a common one. I own an Asus ROG Strix x570 E-Gaming board with two GPUs: an RTX 3090 and a 1030GT. The RTX is placed in the first PCIe slot for optimal performance, while the 1030GT goes into the third slot. I chose this setup because putting the smaller GPU in PCIe_x16-2 could cause airflow issues near the RTX, and I’m okay with the 1030GT’s performance as long as it meets my display requirements.
Now, regarding your question: in the BIOS you can pick PCIe_x16-3 as the first bus interface, which might influence how the system discovers GPUs. However, it doesn’t seem to make a difference. When you add the vfio.pci.ids entry to /etc/default/grub, the system still tries to load the RTX GPU but freezes during startup. There’s no clear way to force the mainboard to use PCIe_x16-3 as the primary host while keeping the RTX in PCIe_x16-1 for passthrough. You might need to check your BIOS settings or consult the motherboard manual for more details on GPU prioritization.
Greetings Igor, I faced a comparable problem with my X370 using MSI and Unraid. To achieve this, I had to activate the WHQL function in the BIOS, which disables another capability called CSM. I believe you should search for a comparable feature that allows you to disable CSM as well. Additionally, it might be necessary to enable specific IOMMU groups, usually located under CPU settings. Otherwise, I can't provide further guidance.
Alright, so after switching off the CSM, I still couldn't get the system to boot with the GPU in that PCIe_x16 (x4 native, chipset) port. But it worked when I set the RTX3090 to run in vfio mode inside GRUB. Now, whenever I selected "Ubuntu" from GRUB, the GT1030 (PCIe_x16_3) display appeared. However, instead of nothing showing, it seemed to freeze on the ROG Gaming logo. I haven’t finished configuring PCIe passthrough yet, but I can boot into Ubuntu/Gnome3 and see that the kernel driver for the RTX3090 is listed as vfio-pci. This makes me think it should still function. I was hoping the GPU would turn off right after choosing "Ubuntu," but unfortunately, it didn’t.
I also noticed the proprietary NVidia driver (with its control panel) isn’t detecting the RTX card anymore, which seems like a positive sign. Next, I need to figure out how to route the keyboard—my mouse is connected via Bluetooth, so that’s not a big issue. I’d prefer the keyboard to go through from host to guest, but it looks like I might need a hardware switch (like the 1-to-4-DP1.4-KVM switch from Level1) to make it work.
Also, I should ensure Windows 10 NVMe stays connected directly to avoid losing performance on games and files. To sum up: there’s no way to force the mainboard to pick that PCIe_x16-3 slot (it didn’t work with PCIe_x16-2 either), and the "Bus interface" option in UEFI doesn’t behave as expected. Mainboards from Gigabyte seem to handle this differently, but I’m not sure. Maybe I’ll try routing the RTX card into a VM only after it’s loaded, rather than before.
Best approach would have been to route the card only when the VM is about to start for Linux tasks. But honestly, it’s going to be step by step. Thanks for your help!