Can You Use a PCIe Express Card In a Slot?

It should be backward compatible, but you will see less performance than if you had it in a PCIe slot since it runs at PCIe x8 instead

The card physically has an X4 interface, so it could be plugged into an X4, X8, or X16 slot It can still physically only access 4 lanes (else

pcie slot x16 Conversely, a PCIe card can fit in a PCIe slot, but again it would be limited by PCIe Those are the absolute basics of PCIe

pcie 4 in pcie 3 slot ssd 2 x16 Gen 4 Card uses PCIe , which doubles the bandwidth per lane compared to PCIe With four slots, it offers up to 256 Gbps of bandwidth per card,