Expansion Cards

PCIe Link Width Sets How Many Lanes Carry Data

A PCI Express slot can look physically large while providing fewer active lanes than its connector suggests. A full-length slot may carry sixteen lanes, eight lanes, four lanes, or even one lane depending on the motherboard design and current resource allocation. PCIe calls these arrangements link widths. Common widths include x1, x4, x8, and x16. The number after the x indicates how many lanes participate in the link. That distinction matters for graphics cards, storage adapters, network cards, capture hardware, accelerators, and other devices that can move large amounts of data through an expansion slot.