The object is to realize power-saving operation in a NIC portion while maintaining a processing ability necessary for services to be performed in a system device having a controller for a multi-CPU process including a NIC. A service request status in a predetermined period is comprehended through a total value obtained by summing weighting values corresponding to types of services and the following energy-saving process is executed in accordance with the total value. The energy-saving is determined whether a protocol process is performed by the NIC or the controller depending on the total value and if the process is performed by the controller, the power supply to the protocol process functional portion and the encryption process functional portion is turned off in the NIC.