Multi-rank memory module that emulates a memory module having a different number of ranks

A transparent four rank memory module has a front side and a back side. The front side has a third memory rank stacked on a first memory rank. The back side has a fourth memory rank stacked on a second memory rank. An emulator coupled to the memory module activates and controls one individual memory rank from either the first memory rank, the second memory rank, the third memory rank, or the fourth memory rank based on the signals received from a memory controller.