The Elephant in the room: AM4/TR4 Chipset IOMMU separation

reikoshea · October 29, 2018, 6:05pm

Am I mistaken in thinking ASRock has it right with the x399 taichi? I was actually looking this up earlier today to pass my raid card to a VM.

ASRock X399 Taichi / Fatal1ty summary Thread Motherboards

Following similar thread for ASUS Zenith Extreme X399, I think it’s worth to create such thread for ASRock workstation oriented X399 motherboards, gathering all workstation oriented info we have. Both motherboards support ECC, SR-IOV and PCI-E bifurcation. Since BIOS 2.00c PCI-E bifurcation supports both x4/x4/x4/x4 and x8/x8 modes (before, only x4/x4/x4/x4) for high end cards like 40G NICs, SAS controllers or GPUs (official answer from ASRock support). Since BIOS 2.00d both x16 slots support bifurcation (before, only bottom one) giving either 16/8/8/8/8/1 or 16/8/4/4/4/4/8/1 or 8/8/8/8/8/8/1 or 4/4/4/4/8/4/4/4/4/8 slots (not counting M.2 -> pcie adapters which can add another 4/4/4). Passthrough story thread: IOMMU grouping with all slots populated: