PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe is a high-speed serial computer expansion bus standard, designed to replace the older PCI and PCI-X bus standards.
One of the fundamental differences between the PCI Express bus and the older PCI is the bus physiology; where 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, PCI Express is based on point-to-point topology, it connects only two devices; no other device can share the connection. This means separate serial links connect every device to the host.
PCIe has numerous improvements over the older bus standards including higher maximum system bus throughput, lower I/O pin count & smaller physical footprint, better performance-scaling for bus devices, a more detailed error detection and reporting mechanism and native hot-plug functionality. The more recent revisions of the PCIe standard support hardware I/O virtualisation.
The PCIe format 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 3.0 is the current production standard and is available on hardware that Sarsen Technology supplies.