PCIe 4.0
4th-gen PCI Express — 16 GT/s per lane.
PCIe 4.0 doubled the bandwidth of PCIe 3.0 to 16 GT/s per lane (2 GB/s usable). It launched with AMD's Zen 2 / X570 in 2019 and Intel adopted it on Rocket Lake in 2021. By 2026 it's the practical floor for any new SSD or GPU; the PCIe 5.0 transition is mostly relevant to high-end NVMe drives and bleeding-edge motherboards.