A memory interface may include: a transceiver module configured to exchange signals with a plurality of dies; and an input/output (I/O) rate controller configured to calculate per-signal-interval ratios of each of the dies by monitoring signals transmitted to, and received from, each of the dies, select a first die whose operating time is relatively slow and a second die whose operating time is relatively fast, among the plurality of dies, using the calculated per-signal-interval ratios, and provide the transceiver module with information for adjusting data interval ratios for each of the first and second dies.