Slow

A site I am working on seems to run so slow on computers that have a smaller processor. The site runs fine on a computer that is 800 but 450 it is just bogged down. The site is not that complex but i am thinking it might be a combo of things that might slow it down. If i have a lot of movements at the same time or tweening while other things are draggable. Does anyone have a suggestion or is it just something i will have to live with