Anyone wishing to construct or upgrade a computer system must have a basic understanding of PCIe slots since it provides the foundation for wise choices regarding free spin slotshardware compatibility and performance enhancement. Knowing how PCIe slots are configured. PCIe slots are made to fit a variety of expansion card types and are available in a range of sizes and configurations. In terms of the number of lanes available for data transfer, the most popular types are x1, x4, x8, and x16 slots.