PCI Express roadmap: The path to 1TB/s with PCI 8.0, the challenges of integration, and beyond

PCIe technology has a rich history and has evolved over the years with each new major revision doubling link bandwidth while maintaining backward compatibility. The introduction of PCIe 6.0 in 2022 marked a significant shift by transitioning to PAM4 modulation, allowing for higher throughput without doubling the clock rate. However, this change comes with challenges such as increased sensitivity to electrical noise and the need for more complex equalization. PCIe 8.0, still under development, aims to double bandwidth to 256 GT/s by 2028, potentially reaching 1TB/s in both directions with specialized hardware like extended-reach cables and high-density sockets being developed to accommodate these speeds. The future of PCIe remains crucial as it serves as the structural backbone of modern computing systems.