PCI Express (PCIe) is the native interface in many processor architectures including most popular x86 processors and often is perceived as chip to chip interface. Other interface options, such as Ethernet, InfiniBandÒ, and Fibre Channel, require additional controller devices that are connected to CPU via PCIe, hence, add extra cost and power, and have higher latency and lower throughput. Consequently, it makes a lot of sense to use native PCIe wherever possible.
In the past, PCIe interface use was limited to connecting the processor to I/O devices. Today, however, PCIe technology allows a broader spectrum of usage models far beyond simple I/O connectivity. PCIe is ideally suited to interconnect multiple processors not only on the same board, but also on different boards or even enclosures.