PCIe

PC Builds

The high-speed expansion bus that links graphics cards, NVMe SSDs and other add-in cards to the CPU and motherboard. Slots and links come in lane counts (x1, x4, x8, x16) and in generations (Gen3, Gen4, Gen5), where each newer generation roughly doubles the bandwidth per lane. PCIe is backward- and forward-compatible: a newer card works in an older slot and vice versa, automatically running at whichever device's generation is lower. Concrete example: a Gen5 graphics card in a Gen4 slot still works, just at Gen4 speeds. Buying impact: you rarely need to chase the newest PCIe generation for gaming, since current GPUs barely saturate even Gen4 x16 — focus instead on having enough x16 and M.2 slots for the cards and drives you actually plan to install.