This client is terrible

I need some answers as to why I can play the game smoothly... but In the client itself pre game it's so terribly laggy it's insane.. constantly missing queues because it lags for 15 seconds during champion select and I don't get to lock in or I do actually get to lock in and then I try to pick my runes/masteries/sum spells and it takes so long for each to pop up and for me to select it I miss 1-2 almost every time.... I didn't have any of these problems with the retired client.. I just wanna play the game B😒😩