Help how to speed up my Samsung galaxy s3..

[vasurb]

when every i try to open my contact there is a lag all ways and when i try to switch between apps my phone hangs a lot . need help asap

thanks

 

[shingamikay]

install root booster. since a recent update it doesnt require root anymore so the name is useless. Set it on speed. It won't do damage and wont drain battery.
Change the launcher to nova launcher. It is a amazing launcher.
Turn off sync and mobile data. Check background apps and close em all. If still does lag than you need a root to get some apps to help u out.
Thats what I did and my phone and tablet work perfect. Some android geeks might tell you a better solution so wait for em.