Two little 'tricks' that might shave off 5C temp from the top card:-
1. Connect the monitor to the bottom card
By doing so, the bottom card becomes the 'master/main' card of the pair. Even under SLI, the main card just does a tiny little bit of work (eg coordinating the 2 cards) which generates a little bit more heat. So, take this little load off from the top card and let the bottom card does it
2. Select the bottom card to be the Physx card
Similar to the trick above, this moves the Physx load to the lower card. And, IIRC, brettjv has a little study that shows this move might even give a slightly higher framerate as well.
And, do you have the P6T or P6T Deluxe V2?
For P6T, there is no gap between the 2 cards but there is still one slot empty for the P6T Deluxe V2.
Before changing the side panel fan from the stock 230mm to 1-4 120mm fans, I suggest you try:
1. adding a 120mm fan behind the HDD cage to direct air into the gap between the 2 cards (pic 1)
2. use an Antec Spot cool fan to do a similar job (pic 2)Edited by windfire - 8/17/11 at 11:40pm