A printed circuit board that plugs into a slot on the motherboard and enables a computer to control a peripheral device. Also called an "interface card," "adapter" or "controller," all the printed circuit boards that plug into a computer's bus are technically expansion cards, because they "expand" the computer's capability. Today, PCI Express (PCIe) is the standard interface (see
PCI Express).
Cards Used to Be the Norm
In earlier PCs, controllers for drives, input/output ports, display, network and sound all resided on separate plug-in cards. Subsequently, peripheral control was built into a chip on the motherboard (see
PC chipset). However, gamers generally install their own GPU cards for faster video performance, and when first installed, the graphics circuit on the motherboard is disabled (see
GPU). See
motherboard and
expansion port. See also
bus extender.
Card Types
Today, PCI Express (PCIe) is the card interface in common use. These are the expansion cards in desktop computers since the IBM PC AT in 1984. For a brief description of each, see
PC data buses. See
PCI Express.
Cards Galore
Cards come in many shapes and sizes, but they all conform to the specific pin format on the motherboard sockets. These are graphics cards and Ethernet adapters with some sound boards thrown in for good measure.