A circuit board that is to be mounted in a connector socket includes a plurality of electrical connectors located along a side edge of the circuit board. Retention bosses are formed on first and second opposite sides of the circuit board, each of the retention bosses protruding from a surface of the circuit board and extending parallel to and adjacent to the first edge of the circuit board. When the first edge of the circuit board is inserted into a slot of a connector socket, contact surfaces of the first and second retention bosses contact top surfaces of the connector socket to help immobilize the circuit board with respect to the connector socket. Adhesive layers on the contact surfaces of the first and second retention bosses may adhere to the top surfaces of the connector socket to help hold the circuit board immobile with respect to the connector socket.