pci slotWhat is a PCIe card? A PCIe card, also known as a PCI Express card, is an expansion card that connects to a computer's motherboard using a PCIe slot.Learn what PCI slot is, how it works and what are the main types of PCI slot (64-bit, 32-bit, PCI-X and PCI-E). Also, explore the history and evolution of PCI slot from 1992 to 2004.