My champion keeps freezing, but the game is still active

Everytime i play arurf, my champion will ramdomly stop moving as well as everything else i can see, but im still able to look around and click, but then the game like "unfreezes" and everything jsut changes, and most of the time i die cause there is an enemy near, any idea on how i can get my game to run smoothly without this "freezing", my game works fine in the normal game modes.