Intel VROC Only Sees One NVMe Drive on Asus Hyper M.2? Fix PCIe Bifurcation on Supermicro X11 First
The root cause: PCIe bifurcation and VMD domains
When all four drives show up on the Asus card but only one lands inside Intel VROC, bifurcation is almost always the culprit. The Hyper M.2 X16 Card V2 places four NVMe drives across a single x16 PCIe slot, but it needs the CPU to split that slot into four independent x4 lanes — written as x4x4x4x4 in BIOS. Without that split, the platform treats the whole card as one PCIe endpoint. Intel’s Volume Management Device (VMD) picks up just one drive, and the remaining three sit in BIOS as plain NVMe controllers. That’s the two-tier view showing up in Device Manager: one drive under the VMD controller node, three listed as ordinary Samsung NVM Express controllers.
Configuring PCIe bifurcation on the Supermicro X11DPH-T
Supermicro buries the bifurcation controls deeper than most consumer boards. The path in BIOS is:
Advanced → Chipset Configuration → North Bridge → IIO Configuration → CPU IOU settingsFind the IOU entry for the physical slot where the Asus card is installed. The X11DPH-T has dual Xeon Scalable sockets, each with its own IIO domain and PCIe slots — make sure you’re editing the right CPU’s IOU. Set the bifurcation for that slot to x4x4x4x4.
Save, reboot, and re-enter BIOS. At this point all four PM983s should appear as separate devices. If they still don’t, cross-check which physical slot the card is in against the slot-to-CPU table in the X11DPH-T manual. It’s easy to install the card into a slot mapped to the second CPU while editing the first CPU’s IOU settings — both CPUs have their own IIO domains and the BIOS presents them separately.
Enabling VMD for the slot
Bifurcation alone isn’t enough. Intel VROC requires the relevant PCIe stack to be placed under Intel VMD control. Still inside IIO Configuration, find the Intel VMD for Volume Management Device submenu. Each PStack (Port Stack) corresponds to a group of PCIe lanes. Enable VMD on the PStack that maps to your card’s slot.
There is one hard constraint here: Intel VROC cannot build a RAID volume that spans multiple VMD domains. All four drives must live in the same domain — which is exactly why putting them all on one add-in card attached to a single slot is the right setup. Once bifurcation is correct, all four lanes come off the same PStack and land in one VMD domain, ready to be grouped into an array.
Samsung PM983 and the VROCSTANDMOD key
The Standard key (VROCSTANDMOD) is Intel’s license for RAID 0, 1, and 10 on both Intel and validated non-Intel NVMe SSDs. The Samsung PM983 is a widely deployed enterprise SSD and appears on most platform validated lists, so the drives themselves are not the reason only one is being seen — that’s purely the bifurcation issue above.
One thing worth confirming: check Supermicro’s supported NVMe drive list for the X11DPH-T specifically. Supermicro sometimes requires a drive to be on their platform-specific compatibility list for full VROC support, even when the VROC key tier technically permits third-party drives. If the PM983 isn’t listed, it may still work in practice, but official support won’t help if something goes wrong.
RAID 5 is off the table with the Standard key regardless of drive brand — that requires VROCPREMMOD. For RAID 10 with four drives the Standard key is the right one.
Creating the RAID 10 array
Once all four drives are visible under the same VMD domain, building the array is straightforward.
- Re-enter BIOS. An Intel VROC option should now appear in the Advanced menu once VMD is active.
- Select Create RAID Volume.
- Name the volume and select RAID 10.
- Select all four PM983 drives as members.
- Confirm and exit. VROC initializes the array in the background.
In Windows Server, install the Intel RST for VMD driver — not the standard consumer-oriented Intel RST package. With the correct driver, the RAID volume appears under the VMD controller in Device Manager and the Server Management utility will recognize it properly for monitoring and alerts.
If bifurcation options are missing from BIOS
Some early Supermicro X11 BIOS releases didn’t expose x4x4x4x4 bifurcation for third-party add-in cards, or showed the option grayed out. Update to the latest BIOS from Supermicro’s firmware download page for the X11DPH-T before assuming the setting doesn’t exist. It sometimes appears after a firmware update. If it’s still absent, Supermicro enterprise support can occasionally provide beta BIOS builds that unlock the option for third-party M.2 adapter cards.
Sources
- supermicro.com
- intel.com
- asus.com
- wq6e.com
- asus.com
- community.intel.com
- cdrdv2-public.intel.com
- pcper.com