But what are your settings in game? Like I said before the biggest hit that FPS takes in FFXI is with the shadows. Do you have them switched on? Even with a system like yours you won't get 30 FPS with shadows on high.
As for Campaign I've read before that it's something to do with the way those zones are programmed. Everyone takes dips in campaign battles at some point. But if the game remains playable I wouldn't worry about it. It's not like Campaign matters as much as a linkshell Dynamis run where performance is key
