[H] Crossfire

[Winterlight]

I have two Asus 4970s installed, mostly because I am running 
three  large monitors, including a 30 inch as the primary monitor. In 
Catalyst control center I can see the check box for Crossfire and I 
have enabled it.

I did not buy the two cards for gaming, but I have them. Does 
Crossfire only work in supported games, or does it work in all games, 
and does it help in 2D use, like video editing. Or  does it 
exclusively output to one display when playing a game? Can somebody 
explain this to me please. Thanks.