1. A memory module operably coupled with a system, the memory module comprising: an insulative substrate supporting a system interface; a plurality of memory devices disposed on the insulative substrate; a memory hub disposed on the insulative substrate and operably coupled with the memory devices and the system interface, the memory hub managing communications between the memory devices and the system interface in response to memory commands received via the system interface; an activity sensing device monitoring activity of the memory module in processing memory commands and generating an output corresponding thereto; and a module power controller operable to direct the memory module to a reduced power state responsive to the output of the activity sensing device indicating activity of the memory module is not of a desired level.