Described is a printed-circuit board (PCB) that supports memory systems in which the memory core organization changes with device width. The PCB includes a memory-controller mounting location and module connectors to receive respective memory modules. Each module connector connects directly to the controller mounting location via a respective set of system data lines that does not connect to any other module connector. System data lines also extend directly between module connectors to support memory configurations with different numbers of modules. The memory systems support one memory module of a wide data width or multiple memory modules of narrower data widths. The number of physical memory banks accessed reduces with device data width, resulting in reduced power usage for relatively narrow memory configurations. Increasing the number of logic memory banks for narrow memory widths reduces the likelihood of bank conflicts, and consequently improves speed performance.