Changes in animation performance in html publish preview

hey all

my developer and i are beginning to work in flash and have a question about publishing deficiencies…

viewing our sequence in flash or as a swf file everything looks great, smooth motion and transitions, no snags whatsoever.

when we publish preview in html the sound plays perfectly yet all of the animation seems to slow down and struggle… like it’s on a slow computer or something.

any thoughts or obvious remarks??? thanks!