Optimizing large groups

1

im making a zombie game and want to have a large number of zombies on the screen at one time, 50+, and so far im controlling them inside a while loop that goes through all of the zombies, and im curious if there is a faster way to control all the zombies at the same time. and also if using something besides movieclips would make a huge difference as well, i want to use the best methods to make the game run smoothly