Screen Freeze, then comes back 10-30 seconds after

Ok so when i play league, randomly my screen will "freeze" (not sure if it actually freezes but thats what im calling it for now) sometimes i loose sound, sometimes i dont. when it "un freezes" my fps is at less that 10 then jumps back up to 120 (have it capped). I checked my graphics card drivers they are all up to date. I dont know if this is a issue other have or if its just me? any help would be greatly appriciated!