A semiconductor memory system including a resistive variable memory device and a driving method thereof are provided. The semiconductor memory system includes a memory controller including a scheduler configured to determine a generation period of a write command; a memory device including a memory cell array, the memory device being configured to write data input from the memory controller in the memory cell array in response to the write command; and a data determination circuit configured to output a change signal to the scheduler when all logic levels of the input data are equal to each other, the scheduler changing the generation period of the write command in response to the change signal.