Provided are a memory device, a memory system, and a method of operating the memory device. A method of operating a memory device including a plurality of random access memory (RAM) chips includes inputting a read command, reading a plurality of pieces of block data including first block data corresponding to the read command from each of the plurality of RAM chips, generating two-dimensional (2D) data by combining the plurality of pieces of block data read from each of the RAM chips, and processing the read command by using the 2D data.