Playback slow in browser, not in Flash player

Does anyone know why my flash file plays back much slower when played in a web browser, but not in the flash player? It is a very complicated file, many layers of many multi-layered movie clips, sounds, the whole deal, but it was always fine when i tested from within flash, or through the flash player itself, but when it plays through the flash plug-in in a web browser it is much slower, which is bad because i have animations that need to synce with music controlled by the sound object. I’m running OS X, and i know, everyone will say that flash is slower on macs than on PCs. But i don’t care about that, i want to know why the speed is different in the player vs. the plug-in. Any help is always very appreciated, thanks.