A configurable memory subsystem includes a memory module with a circuit board having a first and a second memory-containing device (MCD) pair mounted thereto. Each MCD pair has a first MCD in communication with a second MCD. Each MCD has an input port, an output port, and a memory each communicating with a bridge. In response to a command, the bridge transfers at least one of a portion of a data packet from the input port to the output port or to the memory, or transfers a portion of a memory packet from the memory to the output port. A loop-back device receives the command and the data packet form the first MCD pair and transmits the command and data packet to the second MCD pair.