HOW IS MASS EFFECT 2 SO FREAKING SMOOTH BELOW 25 FPS?

Just trying to understand frame rates. I use fraps and no game is enjoyable under 25 fps, no game but Mass Effect 2. Its smooth and its a shooter, and it does not seem effect my skills either. Black flag under 25 fps game me motion sickness, Alan wake was barely playable, but Mass Effect 2 is still really smooth.

What could have been there solution to issues with low frame rates?

author=Dudesoft
It's only smooth if you pick the right courtship dialog.

??? XD