A system includes integrated circuit chip including a first buffer configured to receive signals and a second buffer configured to receive signals, wherein the first buffer receives signals of a higher frequency than the second buffer, a controller chip configured to control the integrated circuit chip, an I/O channel formed between the controller chip and the integrated circuit chip to transfer a first signal and a second speed signal, wherein the first signal has a higher frequency than the second signal, and a status channel formed between the controller chip and the integrated circuit chip to transfer at least one status signal, wherein the integrated circuit chip is configured to select one of the first buffer and the second buffer and actives the selected buffer in response to the at least one status signal and receive a signal transferred through the I/O channel.