On the flip-side of PCI we find PCI-X: an evolution of PCI, which saw most use in servers in its 64-bit version. PCI-X essentially doubles the maximum frequency of PCI (66 to 133 MHz), while ...

This is roughly the same as a PCI-X 64-bit connection (at 133 MHz) if four lanes are used (~1,064 MB/s). Here the PCIe lanes are clocked at 2.5 GHz, with differential signaling send/receive pairs ...

PCIe superseded PCI and PCI-X. Unlike its PCI predecessor, which used a shared bus, PCI Express is a switched architecture of up to 32 independent, serial lanes (x1-x32) that transfer in parallel.

A Switch is defined as a logical assembly of multiple virtual PCI-to-PCI Bridge devices. A PCI Express to PCI/PCI-X Bridge provides a connection between a PCI Express fabric and a PCI/PCI-X hierarchy.