An adapter card with compression-attached memory modules that can be inserted into a conventional vertical connector enables use of CAMMs in systems with vertical memory module connectors. In one example, an adapter card or riser card includes a printed circuit board (PCB) having an edge to be received by a dual-inline memory module (DIMM) connector. First conductive contacts proximate to the edge of the PCB are to be received by the DIMM connector, enabling the first conductive contacts to couple with contacts of the DIMM connector. Second conductive contacts on a face of the PCB are to couple with a first compression attached memory module (CAMM) via a first compression mount technology (CMT) connector. The adapter card includes conductive traces on or in the PCB between the first conductive contacts and the second conductive contacts to couple the CAMM with the DIMM connector.