PCI Express, officially abbreviated as PCI-E or PCIe, is a computer expansion card interface format introduced by Intel in 2004.

It was designed to replace the general-purpose PCI expansion bus, the high-end PCI-X bus and the AGP graphics card interface.

Unlike previous PC expansion interfaces, rather than being a bus it is structured around point-to-point full duplex serial links called lanes.

In PCIe 1.1 (the most common version as of 2007) each lane carries 250 MB/s (250 million bytes per second) in each direction. PCIe 2.0 doubles this and PCIe 3.0 doubles it again.

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