Fps drop when i get into games

ever since hornet’s sting released in some matches when i load in im capped to around 20 to 25 fps for no reason i usually run 80 or 90 on max graphics and when i go back to lobby after these matches i will only get 9 fps and then once i restart the game it will set me back to my normal fps 80 to 90 and it can bug me from the first match til i get off or it wont happen at all its weird ive repaired easy Anti cheat, ended all unimportant tasks, updated my computer any one know how to fix it