A semiconductor device capable of determining plural transfer speeds with a small-scale circuit, and an information processing system having the semiconductor device are provided. The semiconductor device has a frequency determining circuit that receives a data signal on which plural transfer speeds can be set and that determines a transfer speed of the data signal. The frequency determining circuit latches the data signal at each of plural timings continuing with a predetermined interval, detects how many times a data switching occurs consecutively, based on the latched plural data, and determines the transfer speed of the data signal from the result of the detection.