The Dirty Regions option to render only the differences between frames has been there for a while, but never put on by default. This is about to change with the pull requests below. Hopefully this will be the last hurdle to a first beta release of Eden.
https://github.com/xbmc/xbmc/pull/500
https://github.com/xbmc/xbmc/compare/c9eeb85…0e8168e
On paper this is a great new feature. I tried it on a 24 okt build, using the 2: Cost reduction setting, but I had a higher CPU on my asrock ion pc (only looking at cpu status within xbmc and windows task manager). I know its all still in beta, so perhaps thats the reason.
I can also try it on my apple tv 2 if there’s an improvement.