_visible = false vs. removeMovieClip

1

I am just wondering what the differences between these two are. I have an animation that I am trying to make as optimized as possible to get the best possible frame rate. I have clips on the stage that start out visible, but are then set to _visible = false for the remainder of the animation. Basically I am just wondering, is a clip still using cpu power if it is set to invisible? Would it be more optimized to swapdepth the clip to a removable depth, then remove it from the stage with AS? Thanks for any help!