I’m new around here, found this marvelous community while trying to find how to add bifurcation support for this great homelab motherboard.
I even tried to ask Asrock support to do it, but they say its impossible.
However, Xeon D datasheet, section 5.2, page 84/82, states that both PCIe 3.0 root ports on the CPU (not to be confused with the PCIe 2.0 ports from the integrated PCH) can bifurcate down to x4/x4 and x4/x4/x4/x4 https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/xeon-d-1500-datasheet-vol-2.pdf
Can someone here at least confirm if its possible, before we skip to “how” part
I see a IIO menu on the bios, PCIe4 link can be set x4x4 and PCIe6 link x4x4x4x4, x4x4x8, x8x4x4, x8… and a lot more…a quite complex bios but normal as it is a server platform.
A note, Intel specs is one thing, the OEM design and implementation on a motherboard is another side…
And you didnt mentioned the purpose and the needs for the BIF…
EDIT: But the M.2 are on the Marvell 9172 controller…and this may be a dead end on your thoughts about it. Anyway you should wait for another user opinion, from the forum.
Thanks for reply. Board has dual 10gbps network and SAS controller onboard, so not much left for average homelab/ESXi/NAS user to add in those 2 slots…but many would like to add 1 or 2 cheap U2 or NVME SSD, that usually sell at lower price point than SAS counterparts.
Oculink raid cards or dual nvme raid cards with PLX chip raise price considerably
Edit: M2 connectors on board are PCI-E 3.0 X1 and SATA, but that’s not in any way important for bifurcation on two X8 slots.
Board has great expandability for SAS/SATA which is mostly useful for cheap HDD storage…however, many would like to use those cheap U2 SSDs (could get second hand 3.84TB per $230-250 a piece) for speed, mostly for keeping ESXi VMs there, or CHIA plotting and similar stuff that requires speed)
