1. A memory package comprising: a data mover electrically connected to a volatile memory and to a high-density memory vertically stacked upon the volatile memory; the volatile memory comprising: a directory temporarily stored in the volatile memory that maps a volatile memory address to data stored in the high-density memory and a queue that temporarily stores data associated with the volatile memory address at a bandwidth and latency associated with the volatile memory; the high-density memory comprising: a high-density memory portion that stores a copy of the directory, and; wherein the data mover transfers the data stored in the queue to the high-density memory address in the high-density memory as indicated by a map.