GTX 680 2GB FTW Downclocking

Hey,
 
I just purchased 2 GTX 680 2GB FTW cards and I am having a problem with 1 of my cards.  What is happening is when I run a 3d app my video card will randomly downclock to 324Mhz and I have noticed that the Power % is at 275% when this happens.  This problem only happens with one of my cards and this is with stock settings and two different drivers, 301.42 and 304.48.  My power supply is a Corsair AX1200.  I have tried the video card alone and it still randomly drops clocks to 324Mhz.  Not sure what to try to see if my card is bad.
 
Thanks.

I have the same problem with one of my 4GB FTW.   One of the cards will periodically downclock to 324MHz for a few seconds when under load and the power monitor shows the card at 275%.   I swapped the cards in SLI and the issue followed one card.   Then I tested each card individually and found the that one of the GPUs has this power/downclocking issue even when used alone.   I'm returning this card for a replacement.