Built site in as3 but runs slow.. optimizing tips

hey guys, I just built this site in as3. http://www.nextideas.ca

I found it running not so smooth on some computers. Any tips on optimizing, the main background is pretty big but ive seen other sites with major backgrounds lots of happening running pretty smooth.

One idea i had was to create a MASK thats the stage height and width … anyone know if that would slow it all down or speed it up…

thanks in advance guys, i appreciate it :slight_smile: