On motherboards, expansion slots come in a variety of forms, each with a specific function and compatibility for different kinds of expansion cards. Due to its greater speed and efficiency, the PCIe (Peripheral Component Interconnect Express) slot is the most popular type anyono gamed has largely supplanted older standards like PCI and AGP. Different PCIe slot sizes (x1, x4, x8, and x16) correspond to the number of data transfer lanes that are available. High-performance graphics cards usually fit in the x16 slot, but sound or network cards can fit in smaller slots. Older PCI slots are another kind of expansion slot that can still be found in some legacy systems. Due to its slower data transfer speeds, PCIe has largely replaced it, but it can still support a variety of peripherals, including older sound cards and modems.