So for lots of UI interactivity like scrolling etc. it might make sense to automatically adjust the resolution and contrast to optimize for speed (so you know roughly where you scrolled at) and then do a proper refresh once it is idle again. But I suppose this is out of the current scope of the project ...
Scrolling is pretty much worse case. The more of the display you repaint the longer it's going to take.
There's also a trade off...getting faster refresh means worse resolution and contrast.