Fps drops and in-game freeze/crash

The fps drops I noticed started recently, in the last 1-2 patches. my fps just suddenly goes from 60-80 to 01-15. It happens randomly, more so when team-fighting or moving camera. I have all my setting already on lowest they can possibly be. The in-game freezing is what is bothering me indescribably. everything is fine and then BOOM! games frozen, totally. only cursor is moving. I can't even open up task manager. I have to Ctrl+Alt+delete to go to the menu and then click "log out" just to close the freaking game and get back to my desktop. It was fine until this recent patch, happening at least 1-2 time every day since it updated.