1. A method writing data in a resistive memory device having a memory cell array divided into divided into N tiles including a first tile and a second tile, wherein the N tiles are functionally arranged in M groups including a first group including the first tile and 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, wherein the N tiles of the memory cell array are provided on a plurality of layers including a first layer and a second layer vertically disposed under first layer in the resistive memory device.