Peripheral Component Interconnect Express (PCI-E)

PCI Express is a Computer EXANSION CARD designed to replace the older PCI, PCI-X, and AGP standards. A PCIe card fits into a slot of its physical size or bigger, but may not fit into a smaller PCIe slot. Some slots use open-ended sockets to permit physically longer cards and will negotiate the best available electrical connection. The number of lanes actually connected to a slot may also be less than the number supported by the physical slot size. The advantage gained is that a larger range of PCIe cards can still be used without requiring the motherboard hardware to support the full transfer rate—in so doing keeping design and implementation costs down.