PCI Express (PCIe) technology is the most important high-speed serial bus in servers. Due to its high-bandwidth and low-latency characteristics, PCIe architecture is widely used in various server interconnect scenarios, such as:
- Within a server: CPU to GPU, CPU to network interface card (NIC), CPU to accelerator, CPU to SSD
- Within a rack: CPU to JBOG and JBOF through board-to-board connector or cable
- Emerging GPU-to-GPU or accelerator-to-accelerator interconnects
At the same time, with the rapid development of heterogeneous computing, the data-throughput requirements in the server system are becoming increasingly higher. Two years after the release of the PCIe 4.0 Base Specification, the PCIe 5.0 Base Specification was officially released in May 2019 to address these requirements.