Memory architecture having ranks with variable data widths

Ranks of one or more memory modules can have variable data widths. As part of initializing a memory architecture, a memory controller can be configured to detect the data width of the ranks in the memory architecture. Based on the detected data widths of the ranks, the memory controller can synchronize the clocks and chip select signals of multiple ranks to thereby cause one or more memory chips in each of the multiple ranks to be connected to the shared data lines at the same time.