Client Bug

I am dealing with some kind of client issue. At first I thought it was only because of packet loss but then, after i tried and solved all possible causes for packet loss, I realized it could be something else. It take a lot of time to log me in int the game, the game reaction time is very slow (just like having a poor internet connection, even if my internet is good and stable), there are a lot of champ select problems too, i cant see or see very late the chat in champ select room, most of the time i cant ban or pick the champ and even the start queue button doesn`t work properly. I have tried to repair the client 2 times already but nothing changed.