Click Click Click... power supply sound?

I got an OCZ ModXstream 700W and recently I am hearing some strange sounds when I am playing over an hour. It seems to be comming from my power supply, but since my 2 graphic cards and 2 fans are the same place, I am not sure which one it could be.

If I go logically, the 2 fans and the 2 graphic cards would not make that sound. COuld it be possible that my power supply is dying? It's only 10 months old. If so, would it worth 20$ for sending it back to OCZ?