A memory device for use with a primary power source includes: volatile memory including a plurality of memory portions each of which has a normal operating state and a low-power state; an interface for connecting to a backup power source arranged to temporarily power the volatile memory upon a loss of power from the primary power source; a non-volatile memory; and a controller in communication with the volatile memory and the non-volatile memory programmed to detect a loss of power of the primary power source and in response to move data from the volatile memory to the non-volatile memory at least one memory portion at a time, and while moving data from the volatile memory to the non-volatile memory place the memory portions from which data is being moved into a normal operating state and the memory portions from which data is not being moved into a low-power state.