Thanks very much for the suggestions.
Sorry for being vague, I guess what I'm trying to ask is if there any situations where GSAP has some internal optimisation and would not tween an item. For example, if I remember correctly my old days from using Flash, if a movieclip has an alpha of 0 then it is still rendered, but if visibility is set to false then it is NOT rendered.
In my project, I'm looping through each of the items and animating them like this:
TweenLite.to($(this), scrollspeed/1000, {top:np + "px", force3D:true});
So, for any items not visible within the viewport, I don't really want to waste time tweening them. Would it be best to simply set the visibility to hidden, turn off pointer-events and set scrollspeed to 0 for off-screen items or is there a better way to do this?