to a computer system. Sometimes the design of the computer's case and motherboard involves placing most (or all) of these slots onto a separate, removable card. Typically such cards are referred to as a riser card in part because they project upward from the board and allow expansion cards to be placed above and parallel to the motherboard.

Expansion cards allow the capabilities and interfaces of a computer system to be extended or supplemented in a way appropriate to the tasks it will perform. For