Systems, methods, and apparatus related to a memory system that manages an interface for a volatile memory device and a non-volatile memory device to control memory system power. In one approach, a controller evaluates a demand on memory performance. If the demand of a current computation task needed by the host is high, a DRAM device is powered-up to meet the demand. Otherwise, if the non-volatile memory device is adequate to meet the demand, the DRAM memory is partially or fully-powered down to save power. In another approach, a task performed for a host device uses one or more resources of a first memory device (e.g., DRAM). A performance capability of a second memory device (e.g., NVRAM) is determined. A controller of the memory system determines whether the performance capability of the second memory device is adequate to service the task. In response to determining that the performance capability is adequate, the controller changes a mode of operation of the memory system so that one or more resources of the second memory device are used to service the task.