Abstract: A memory module includes a mother board with an edge connector mounted adjacent one of its edges. Memory chips are mounted on the same side of the mother board as the edge connector. A daughter board, having memory chips mounted on its surface facing the mother board, is connected to the mother board so that its maximum height above the mother board is substantially no greater than that of the edge connector. Preferably the memory chips are mounted in thin TSOP packages and the daughter board is connected to the mother board by two rows of mating electrical pins and sockets, one located near the edge connector and the other near the top of the mother board, so the daughter board is mounted over virtually all of the width of the mother board except that covered by the edge connector, and so that the rows of mating connectors and the facing surfaces of the mother and daughter boards form an air channel through which air can flow to cool the memory chips mounted between the mother and daughter boards.