Stupid question, is all of this what I'll need?

Is the board SLI compatible? I don't see it on the board, and even looking it up on newegg I see it comes with a bridge, but not that it is. I ask because you have a massive overkill PSU, but won't need anywhere near that much power. Even if you were running SLI you won't be crossing 600W. Unless you are OCing. Is there a reason for a PSU that large?