ActionScript 2.0 :: Main Animations Slow Down A Huge Bit When Using Internal Movie (several Frames)

To try to avoid lag in the main animations (few ones, 5 I think), instead of having all the contents load as external movie clips in a movie clip called contentsMC (for instance), I used that contentsMC clip to contain them all, in several frames. There's no great problem in having all in one, since the contents are mainly text. The contentsMC shows up in a masked area inside the main movie clip.

I also have a transition effect, under that masked area.

When I press a button, it uses the command loadContent = #; And sets the transition effect movieclip play ( transitionMC.gotoAndPlay(1); ).

At the mid point of that transition effect (when it covers the actual content), it has the if conditions required to display what was asked.

if (loadContent == 1) {
_parent.contentsMC.gotoAndStop(1);
if (loadContent == 2) {
_parent.conteudos.gotoAndStop(2);

and so on.

However, when the transition effect is ocurring, all the animations in the main page become really slow, until it ends. Also, if I use anything inside the contentsMC, such as a scroll bar, the same lag occurs. That lag happens both with the always running animations (they are 5, I think) and with any other animation triggered during that, for instance by the onRollover effect of a movieclip.

To try to reduce that, I had set the framerate to higher values. First I set it to 50, then 60, and now it's currently at 90 (I only set it to 90 as it displays quite slower on the browser)