Irregular Framerate after patch 8.23

So, i've been playing league on a Laptop for around 3-4 months, and i've never had this problem before. Before patch 8.23 i had a costant framerate around 60, with all the option to keep the game smooth (low graphics, framerate ceiling, etc.). Recently, after patch 8.23, my games have been terribly frustrating cause my framerate keeps dropping from 60, to 40, to 20, going back up, and dropping again. i tried to test it vs bots, in training tool, and it's always the same. i've tried several methods like uninstalling and reinstalling, checking computer performances, looking for possible bottlenecks, but i haven't found anything. I don't know if other players are having the same issues. I'm playing from EUW