1. A method writing data in a resistive memory device having a memory cell array divided into at least a first tile and a second tile, the method comprising: receiving a write command and corresponding write data; and executing a write operation defined by the write command and write data by: performing a first simultaneous write operation by performing a set write operation on resistive memory cells of the first tile while simultaneously performing a reset write operation on resistive memory cells of the second tile in response to the write command; and performing a second simultaneous write operation by performing a reset write operation on resistive memory cells of the first tile while simultaneously performing a set write operation on resistive memory cells of the second tile in response to the write command.