A memory module assembly includes a printed circuit board (30) having a heat-generating electronic component (32) thereon, a heat sink (10) and a clip (20) for securing the heat sink onto the heat-generating electronic component. The heat sink includes a base (12) and a plurality of fins (14) arranged on the base. A plurality of recesses is defined in the heat sink. The clip includes a body (22) resting against a face of the printed circuit board and elastic hooks (24) extending from the body. The hooks are received in the recesses and resiliently press the base of the heat sink toward the heat-generating electronic component, whereby the clip clamps the heat sink and the printed circuit board together.