A memory module assembly includes a printed circuit board having a plurality of heat-generating electronic components thereon, first and second heat sinks formed by stamping a metal sheet and attached on opposite sides of the printed circuit board and a clamp clamping the first, second heat sinks and the printed circuit board together. The first and second heat sinks each comprise a plurality of fins extending therefrom and define a plurality of openings between the fins. The fins and openings are alternately arranged on each of the first and second heat sinks along a height direction thereof. The second heat sink includes a pair of positioning tongues extending from opposite side edges thereof. The first heat sink engages with the second heat sink via the positioning tongues of the second heat sink extending in and engaging with the first heat sink.