I have also been encountering this problem, only since I updated to 1.6.0.1 (I never tried 1.6.0.0). Of relevance: I noticed that the FPS drop comes and goes even when I am looking at the same thing. In other words, it is not graphics dependent. In one instance, I was inside of a house covering a door for an extended period of time. Every so often (at seemingly random intervals) my FPS would suddenly drop significantly, causing things to become very stuttery. Usually within 10 minutes it would return to normal and be smooth as silk even though the image on the screen was the exact same. The only correlation I can possibly draw is that in every FPS drop there were other players around. However, I have often been near other players and had "good" FPS as well. Game Settings: "Very High" Resolution: 1920x1080 System: Windows 7 Intel Core i7 930 ATI HD6950 2G Onboard RAM 16 GB RAM