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).
Added updated info based on BIOS 2.00d. It’s monster board. Also I think we should take a while to appreciate how awesome is ASRock support which implemented 2 new, totally optional, nice-to-have functions in 2 weeks by request in support ticket… Now we can hook up 14 gpus to this motherboard for “14 gamers, 1 cpu” lol.
Considering that 2.00d was created yesterday and sent in zip (2.00c was created 1 week ago) I would say yeah it’s probably not public yet. I’m sure you can poke them to send you one as well as give answer to AGESA question. They sent me particularly Taichi BIOS but those boards are almost 1:1 so I doubt they didn’t add it to Fatal1ty as well.
Fun fact - with SR-IOV and bifurcation support thus 14 pci-e slots those motherboards have hypothetical capacity to run 448 VMs with accelerated graphics… or 192 when using only x8 slots (with 32 vGPUs per S7150x2 card, 24 VMs in high performance mode 4gb/vGPU, 4 per card) . You’d need lots of optane for swap tho.
I’m interested in the same except I will be going for a cheaper 1920X or 1950X.
I am looking to make a build that has Linux Host, Windows VMs for gaming and work apps(2-3 VMs), FreeNAS/other VM for NAS, and maybe a couple more VMs to host a website for my wife’s business and maybe another for myself which is another business.
Soo, I was wondering something about PCIe bifurcation… It’s mentioned in the OP that both x16 slots now support bifurcating into various configurations, which is great. But how about the x8 slots? Could support for x4/x4 be added to those or is there a technical limitation preventing that? I’m contemplating building a dedicated VM host at work and the more PCIe devices the better. Any thoughts?