[SOLVED] I need help setting up double gpu passthrough

The key point is that no motherboards exist that split a 16-lane slot into two 8-lane slots, except for high-end chipsets. (It may exist, but it is rare.)

The Ryzen CPU lanes are 24 lanes for the 5700X3D. Four of these lanes are reserved for the connection between the chipset and the CPU and are not available to the user.

*On the motherboard, the CPU lanes are designed to be used regardless of the chipset.

The remaining 20 lanes can be used in configurations such as x8x4x4x4, x8x8x4, or x16x4. (Depending on the motherboard or BIOS design)

If there are no iommu issues and you are not dissatisfied with x4 connections, the x16x4 configuration is actually perfectly fine.

*Multiple people are probably playing using an eGPU like the x4 connection (Oculink)

*ECC support is complicated, so I don't know.
 
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leesteken said:
No:
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It's really crazy.
The MSI B550-A Pro seems to be the only board that has two PCIe slots connected to the CPU and not End Of Life.
Unfortunately, for some reason, the MSI doesn't support ECC. :(

I'd even be happy with a second PCIe slot, even just x4, but I can't find a B550 board with that. :(
 
brightrgb said:
The MSI B550-A Pro seems to be the only board that has two PCIe slots connected to the CPU and not End Of Life.
Unfortunately, for some reason, the MSI doesn't support ECC. :(

I'd even be happy with a second PCIe slot, even just x4, but I can't find a B550 board with that. :(
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Only the first PCIe x16 slot and the first M.2 slot (which is like PCIe x4) are usually connected to the CPU and can be used for PCI(e) passthrough. What makes you think the second slot will put a GPU (or other PCIe device) in a separate IOMMU group (without using the pcie_acs_override)? Only the X?70 chipsets support two PCIe x61 slots (both at x8) as far as I know.
 
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