A lot of Apple's apps are using hardware acceleration for zoom / scroll now. The graphics card is used to transform a 'snapshot' while you are dragging etc and the actual redraw happens only when you stop moving. It's very clever and makes things feel very smooth.
My colleague likes to use audio for drum parts and when you get things like hihat patterns as individual regions, moving around in the arrange can get painfully sluggish even on a beefy quad core. It's a waste of resources to have logic repeatedly render every little region for every 'frame', it need only happen when u stop moving. They obviously already have the frameworks for this as you can see it throughout OSX.
