PCIe vs NVMe: What's the difference?

cards with a B Key interface can only fit into a B Key host slot, and likewise for M Key But cards with a B+M Key design can fit in either

slot: Can support both SATA and PCIe SSDs, but the keying determines which type of SSD can be inserted It's not related to PCIe slots on

nvme slot Only if its a boot device or your intent is software raid, any most pcie adapter regardless of bios support will support an nvme data drive once

nvme pcie 40 in 30 slot Front-accessible slots available; More PCIe connections for greater PCIeNVMe support Rear: Up to 10x PCIe slots, plus a slot dedicated to the OCP adapter