Hai ever since I downloaded and installed the patch i have to start the game via the "run as Administrator" also I went from 50 FPS to 9 with lagg hacks all the time durning encounter.
Some info would be nice. Did you move your installation directory? What are your computer specs? What in-game settings are you using and have you tried tweaking down shadows, anti-aliasing and liquid details? Tried disabling addons?