An SSD will make no difference at all to Flash smoothness for things llike animations and page scrolling. And Flash dont use the GPU for anything but video so your GPU wont do anything here for scrolling. Maybe try the Flash Player 11 release candidate? That can use the GPU for all graphics now, but the content has to be made to use it, it wont automatically work. If it's the browsers scroll bar you mean though, and not a scroll bar inside Flash, thens it's likely the browser or a add-on.
It's odd though, because Flash, like most things, is known to usually run worse on Macs.