A memory module, which includes at least one memory stack, comprises a plurality of DRAM integrated circuits and an interface circuit. The interface circuit interfaces the memory stack to a host system so as to operate the memory stack as a single DRAM integrated circuit. In other embodiments, a memory module includes at least one memory stack and a buffer integrated circuit. The buffer integrated circuit, coupled to a host system, interfaces the memory stack to the host system so to operate the memory stack as at least two DRAM integrated circuits. In yet other embodiments, the buffer circuit interfaces the memory stack to the host system for transforming one or more physical parameters between the DRAM integrated circuits and the host system.