I have to displays connected to my HD 6950 - a 37" FullHD Samsung TV and a 23” Dell UltraSharp U2312HM. When the Samsung one is the only display enabled I get considerably lower average fps while gaming than when the Dell one is the only display enabled.
For example: These are the results after using Fraps while playing the same sequence in the game Prototype 2:
Also, I've discovered that when I use the "Duplicate These Displays" option. I get the same high FPS as with working with the Dell alone. Why do my fps drop in the Samsung TV when it's enable alone, but not when in duplicate mode with the Dell?
What the hell is happening here? Something is seriously messed up...