pci slotLearn about PCI, a standard information transport for extension cards in computers from 1993 to 2007. Find out the types, function, advantages and disadvantages of PCI slots and how they differ from PCI Express.PCIe slots come in a variety of physically different sizes referred to by the maximum lane count they support, ie. x1, x2, x4, x8, x16, and x32. A PCIe card will fit into a slot of its size or bger,