That's actually normal for the PS4 version. In a less dense populated area you will get 60 fps, but when you move to a large area with other players then you can forget the 60fps. All you can do like on PC is limit the amount of characters that are displayed on screen at once. The PS4 is a huge step over the PS3 version, but in no way shape or form is it anywhere near performance wise to a good PC.