Well, I have a very good spec myself, including a Vertex 2 (which isn't the best SSD), and, with the new server's player limit, this happens to me as well. My FPS used to drop to 95 at much, but, with 200 players, it was worse.
So I suppose it's just the game's optimization, like always. Because, even after lowering most settings, it wouldn't improve.
The only games I've seen run at maximum FPS all the time are CoD 4, Crysis 2, and only a few others.