How many drives can I run in my system with this adapter?
A single PCIe slot at any speed without bifurcation can only support one SSD. The slot must support x8/x8 or x4/x4 (such as x8 + x4/x4 over two slots) to expose two SSDs in the corresponding M.2 slots. The slot must support x4/x4/x4/x4 to expose three or four SSDs. If no drives show at all, confirm that the PCIe slot has no conflicts in your motherboard manual. SSD bandwidth will depend on the slot generation at up to four lanes per SSD.