If i have the same hardware circuit for example for driving a motor, how is it possible to give peak performance once and continuous performance other time? Since the components are same, should it not have same behavior every time?
you don't give much information, so we have to guess.
Motor: If you talk about motor current, then maybe the peak current for starting the motor is OK, but it can´t hande the same current continously because of power dissipation and resulting heating.
This is no different than saying a loudspeaker has a peak power handling capability (for a specific duration) and an average continuous power capability.