Cycles: 1

KillSprite stops any thread in a precise time, whereas the flag KillClip used in Start only makes a sprite disappear once it lefts the screen.

If the sprites have to be present on the screen performing a determined movement, the best way to free slots for the next ones to come in the cheaper ay in terms of cycles wasting, is to kill'em at exact moment they left, instead of let the code to check for a KillClip flag.