Fps problem since patch 9.2 till now(9.6)

The game is unplayable for me,my fps goes up and down all the time+in teamfights i get like 39fps which makes it very hard to play.Before i had league on medium graphics with minimum of 90 and 70fps in teamfights(now with very low settings i get minimum of 39).Now it makes some weird freeze screen things,fps unstable,not smooth at all.I dont know whats happened with the game.Any solutions and suggestions are helpfull.