The present invention relates to a memory system having a memory device with two clock lines. One embodiment of the present invention provides a memory system comprising at least one memory device, a memory controller to control operation of the memory device, a first clock line which extends from a write clock output of the memory controller to a clock port of the memory device to provide a clock signal to the memory device, and a second clock line which extends from the clock port of the memory device to a read clock input of the memory controller to forward the clock signal applied to the clock port of the memory device back to a read clock input of the memory controller. The memory device may further comprise a synchronization circuit adapted to receive the clock signal from the memory controller and to, provide an output data synchronized to the forwarded clock signal.