When a movie clip's _visible property is set to false, does flash still render
the content of the movie clip? I'm trying to combat lag when scrolling large
amounts of pictures, drawings, etc, and to do this i'm trying to get flash to
not render the graphics outside of the visible region, the stage. I didn't
think Attaching and removing the movie clips with attachMovie() and
removeMovieClip() would be fast enough.

Also, i'm using Flash MX, not MX 2004.

Thanks in advance.

if a movieclip remains instantiated, flash has to keep track of it whether it's
visible or not and therefore it's going to eat cpu cycles whether it's visible
or not. you must use removeMovieClip() to decrease the drain to decrease the
cpu load due to any movieclip created with actionscript.

Well, besides keeping track of whether its visible or not, will flash have to
keep track of the contents of the MC? I'd think not if it was invisible, but
i'm unsure, and that's basically what i was asking. And since i'm going to be
adding and removing content very frequently, i think that flash keeping track
of the visible property would eat less cpu cycles than adding and removing
movie clips all the time would. I'm I right to assume that?

no, flash would need to track everything in a movieclip whether it's visible or
not. flash would have no way of knowing whether you intended to change that
movieclip's _visible property back to 1 or not. and if you turned it back to
1, you sure would expect nothing to be lost.