Severe fps drop since update

Since the update, whenever joining a realms server, you can play for maybe 15 minutes before the fps starts dropping severely. Changing any graphics settings doesn't make a difference. Sometimes if it starts to drop and you open the pause menu, it resets it for another 15 minutes then it starts dropping again. You can only do this once before you end up having to leave and rejoin to fix. This is happening everyone in the realm. The owner has tried changing regions and removing add ons but nothing has helped.