[CLIENT] Slow in champion select

Every time I get into the champion select screen the game starts lagging to high heavens, I can't see any chat and If i click on a champion it brings up the waiting for response from server until it times out saying unknown error has occurred and the only way I can get into the game is if i close down and restart the client and hopefully that champ i have clicked on is the one i want and can be put in the position left off as I haven't been able to see who wanted to go where or what anyone else has picked. And no way can I play any ranked as it just doesn't work.