Peripheral Component Interconnect (PCI)

Peripheral Component Interconnect, or PCI, is a bus system for connecting expansion cards to the mainboard of servers, workstations and PCs. The classic PCI bus operated in parallel with shared bandwidth and has been replaced by PCI Express, or PCIe. PCIe transfers data serially over individual lanes, configured per slot as x1, x4, x8 or x16, each forming a dedicated point-to-point connection. With every generation from PCIe 1.0 through PCIe 5.0 and beyond, the data rate per lane doubles. Components connected via PCIe include network interface cards, RAID and HBA controllers, NVMe SSDs, GPUs and storage expansion adapters. Key selection criteria are the generation, lane count, card form factor and the slots available in the server.