Soo, the FPS rate randomly goes down, my mosue sometimes stops listening to me and some beep sounds.

Okay so sometimes in the game, the FPS goes down, when that happens the mouse stops listening too, that means it's not moving and also after that stops i hear from 3-10 beeps, depending on how triggered i was when that happened. Also when i try to write in chat, i press the letters but they go slow to appear in the chat.[sg-shisa]

Note:this problems appear only on league when I am in the game.