using "htop" ("apt-get install htop") or top command you'll find which proccess exactly causing it, if it's X.org, it's probably nvidia blob fauls, so sadly CANTFIX in our side :)
using "htop" ("apt-get install htop") or top command you'll find which proccess exactly causing it, if it's X.org, it's probably nvidia blob fauls, so sadly CANTFIX in our side :)