My Nexus 5x runs like crap, very slow and closes apps when I do 2-3 things at a time (music, gym app, browser for example). I tried everything, reinstalled 7.X

My Nexus 5x runs like crap, very slow and closes apps when I do 2-3 things at a time (music, gym app, browser for example). I tried everything, reinstalled 7.X system, installed 8.0 on launch, removed most of the apps... Btw, removing facebook and messenger apps helped very much. Now I use messenger lite and don`t use facebook on the phone (thanks, Google :) ). Was waiting for new phone releases, but maybe for the first time I will try an iPhone, I just hope iOS is not that limited and bad any more.