WILL GIVE BRAINLETS PLEAS ANSWER FAST I ONLY HAVE 5 MIN'S LEFT UNTIL I HAVE TO TURN IT IN. How do instantaneous speed and average speed differ? Instantaneous speed happens all the time, but average speed only happens once per hour. Instantaneous speed is always faster than average speed. Instantaneous speed is the speed of an object at a specific time, but average speed is the total distance over the total time. Instantaneous speed is always slower than average speed.