Playback performance tips for Flash movies
Performance of Flash movies can vary greatly, depending on the options in effect and the playback environment. The following are tips for getting optimal playback performance from Flash:
If adequate for your needs, use the Low quality setting rather than High. Using Low turns off anti-aliasing, which speeds up Flash animation rendering. A handy technique is to switch the quality of the sprite to Low while displaying a fast-moving animation sequence (such as a spinning logo), and then switch the quality back to High on the fly as the animation slows down or comes to a stop. This way, performance can be improved during the part of the sequence where it would be more difficult to perceive the improved quality anyway, without sacrificing quality in the end result.
Experiment with different system color depths to see what provides the best performance. For example, some graphics, such as gradients, display faster at 16 bits.
Use Copy ink if possible. Transparency, using Background Transparent ink, requires much more processing time. If your Flash sprite is in the background (no other Director sprites are behind it), use Copy instead of Background Transparent, and author your Flash movie in such a way that its background color is the same as the background color you chose for your Director Stage.
Use Direct to Stage if possible. Layering and transparency are not supported in this mode; however, if you just want to play a Flash movie within a box with the best performance possible, this may be the way to go.
Make sure that the Director movie tempo is set high enough. Unless you’re using Direct to Stage, your Flash movie will not play faster than the Director movie frame rate, regardless of the frameRate or fixedRate setting. For smoothest playback, set the Director frame rate to at least 30 frames per second (fps).
Use Lock-Step or Fixed playback mode to adjust the Flash movie frame rate. Lock-Step gives the best performance, because playback of the Flash movie is synchronized to the Director movie frame for frame.
Set the static property of the sprite to TRUE if your sprite contains no animation (such as a static block of text) and doesn’t overlap other moving Director sprites. This keeps Director from redrawing the sprite every frame unless it moves or changes size.
When modifying Flash properties using Lingo, set the properties for the sprite rather than for the cast member. Setting the properties for the cast member modifies values at the cast member level and broadcasts the change to all sprites on the Stage. This overhead can affect performance. If you have only a single sprite for the cast member, modify the sprite property directly.
Avoid using more Flash sprites on the Stage at the same time than necessary. Each Flash sprite loads its own instance of the Flash Asset Xtra into memory, which can slow performance.
Limit the amount of Lingo that executes while the Flash movie plays. Avoid tight repeat loops between frames. The usual Director performance optimizations apply when using Flash movies.
If you import compressed SWF files (new in Flash MX), be aware that Director will use memory for both the compressed and uncompressed versions of the file until the file has been completely uncompressed into memory.
This is from the director MX help though applies for 8 and 8.5
but i must say that flash mx files run pretty smooth in director mx, even if its a complex animation.