Site lags in HTML, but quicker in .swf

I’ve just started working on a new site and while testing, noticed that it lags in the .html page, but as a standalone .swf, it’s keeping up to speed. Why???

I know there are ways to optimize the site to reduce file size, but I don’t have that much in the file yet really. I am using alot of _alpha transitions though on the timeline, which I know bogs it down a bit, as well as a large graphic (.jpg) image in the background, which fades in.

Any ideas on how to reduce my file size considerably?

thanks ~ :book: