A memory device is provided as follows. A memory cell array includes a plurality of memory cells, and the plurality of memory cells are divided into a first memory group and a second memory group. A first page buffer group is coupled to the first memory group and includes a plurality of first page buffers. A second page buffer group is coupled to the second memory group and includes a plurality of second page buffers. The first page buffer group performs a first data processing operation on data stored in the first page buffer group and stores a result of the first data processing operation. The second page buffer group performs a second data processing operation on data stored in the second page buffer group and stores a result of the second data processing operation. The first and second data processing operations are performed at substantially the same.