In contrast, PCI Express is based on point-to-point topology, with separate serial links connecting every device to the root complex (host). One of the key differences between the PCI Express bus and the older PCI is the bus topology PCI uses a shared parallel bus architecture, in which the PCI host and all devices share a common set of address, data and control lines. Ĭonceptually, the PCI Express bus is a high-speed serial replacement of the older PCI/PCI-X bus. For instance an x16 slot with only 4 PCIe lanes is quite common. Sometimes what may seem like a large slot may only have a few lanes. The PCIe slots on a motherboard are often labelled with the number of PCIe lanes they have.
2.1.1 Non-standard video card form factors.More recent revisions of the PCIe standard provide hardware support for I/O virtualization.ĭefined by its number of lanes, (the number of simultaneous sending and receiving lines of data as in a highway which features traffic in both directions) the PCI Express electrical interface is also used in a variety of other standards, most notably the laptop expansion card interface ExpressCard and computer storage interfaces SATA Express, U.2 (SFF-8639) and M.2.įormat specifications are maintained and developed by the PCI-SIG (PCI Special Interest Group), a group of more than 900 companies that also maintain the conventional PCI specifications.
PCIe has numerous improvements over the older standards, including higher maximum system bus throughput, lower I/O pin count and smaller physical footprint, better performance scaling for bus devices, a more detailed error detection and reporting mechanism (Advanced Error Reporting, AER), and native hot-swap functionality. It is the common motherboard interface for personal computers' graphics cards, hard disk drive host adapters, SSDs, Wi-Fi and Ethernet hardware connections.
PCI Express ( Peripheral Component Interconnect Express), officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards.