A surgical instrument system can comprise a surgical instrument for use with a loading unit comprising an end effector, wherein the loading unit is releasably attachable to the surgical instrument. The surgical instrument comprises a motor configured to drive a firing member and is configured to determine whether the loading unit includes a datum identifying the loading unit or is otherwise identifiable. If the loading unit is identifiable, then the motor of the surgical instrument fires a first firing rate. If the loading unit is not identifiable, then the motor of the surgical instrument fires at a second firing rate.