A method for carrying out read and write operations in a synchronous memory device having a shared I/O, includes receiving a read command directed to a first internal memory bank during a first timeslot, activating the first internal memory bank to access read data at a read address requested by the read command, receiving a write command directed to a second internal memory bank during a second timeslot later than the first timeslot, determining whether a data collision between the read data for output to the shared I/O with normal read latency and write data to be received on the shared I/O with normal write latency would occur, and receiving the write data on the shared I/O with the normal write latency during a third timeslot later than the second timeslot.