Dec. 11, 2025 –
By by Tam Do, technical marketing, business development, data center and AI infrastructure, Microchip Technology Inc.
EDN
Peripheral Component Interconnect Express, or PCI Express (PCIe), is a widely used bus interconnect interface, found in servers and, increasingly, as a storage and GPU interconnect solution. The first version of PCIe was introduced in 2003 by the Peripheral Component Interconnect Special Interest Group (PCI-SIG) as PCIe Gen 1.1. It was created to replace the original parallel communications bus, PCI.
With PCI, data is transmitted at the same time across many wires. The host and all connected devices share the same signals for communication; thus, multiple devices share a common set of address, data, and control lines and clearly vie for the same bandwidth.
With PCIe, however, communication is serial point-to-point, with data being sent over dedicated lines to devices, enabling bigger bandwidths and faster data transfer. Signals are transferred over connection pairs, known as lanes—one for transmitting data, the other for receiving it. Most systems normally use 16 lanes, but PCIe is scalable, allowing up to 64 lanes or more in a system.