For some reason, at the moment, the app takes up a lot of system resources, relatively. I don't know if it is related to Twitch, but it is problematic. I hope you can get rid of such a problem when you move to the new app?
Would you mind sending us some report or log? We've run some tests and admittedly haven't found heavy-duty system requirements from the Twitch app during navigation, downloading etc.
Some modpacks (texture packs in particular) require a hefty amount of RAM, but if you could send us any documentation it'll help us look into this!