A data processing system includes a central processing unit (CPU), a control block configured to interface with the CPU, a cache memory configured to interface with the control block and arranged to be spaced from the CPU by a first distance, and a combined memory block configured to interface with the control block, arranged to be spaced from the CPU by a second distance larger than the first distance, and configured of a working memory and a storage memory. The combined memory block is configured of a plurality of stacked memory layers, each configured of a plurality of variable resistance memory cells. The working memory is allocated to one memory layer selected among the plurality of memory layers. The storage memory is allocated to remaining memory layers among the plurality of memory layers.