I’m using a dual NVMe PCIe expansion card so I can take two separate NVMe drives that were eating up two motherboard slots and consolidate them into a single x8 slot. On paper it looks like “plug it in and go,” but the catch is that each NVMe drive is its own PCIe device that needs four lanes. If your motherboard isn’t set up to look for multiple devices behind that one slot, you’ll only see one drive—this is where PCIe bifurcation comes in. In this video I walk through PCIe bifurcation on a Supermicro X10SRi-F, including how the six slots are numbered and which ones actually matter (PCIe 3.0 slots 3 through 6). I use the motherboard block diagram to show how the CPU’s 40 PCIe lanes are split across ports and slots, and why that immediately rules out certain slots for a dual-NVMe adapter. Then I jump into the BIOS (Advanced > Chipset Configuration > North Bridge > IIO) and set the correct bifurcation mode (x4/x4) on the right port so both drives enumerate. Finally, I verify in the OS that both NVMe devices show up and that my mirrored array is still clean and healthy.