Open your system up and start running a game or a benchmark to get the GPU going and watch the fans and see if you can tell what is happening. Also try removing the card and manually checking to make sure nothing is in there and that nothing has come loose.
I checked, nothing was in it's way.
It was kinda loose though, but I tightened it as much as I can and it was still making the noise.
Here is a video that I made http://www.youtube.com/watch?v=vo_Vtrxvwok