The MSI LXE cards have been carefully overclocked to 950/1900/2200 and phys X assigned to the second card.
Running in performance mode via Nvidia control panel using Beta 285 software yielded a Afterburner Log of 2.1 Gig max used memory per card for a total of 4.2 during the game.
Frames is unknown as I have the temp monitor on instead. However BF3 Beta should give you alt/shift+3 for Frame rate .. I THINK...
Alpha and Beta going, now Retail soon. I hope to replace my DSL for 10 up/ 10 down Mbit fiber optic in the near future.
I also jammed a old Antec 900 fat boy 200 mm fan set on high between the hotswap drive cages/Power cable cage and resulted in the lower card being cooled down to 27 C idle and 35 C gaming while the top card shows 33 C idle and 57 C gaming.
You will lose the PCI e slot between the cards. The fans are just too big.
I am half tempted to hack together in a Metal shop a box for both the cards with fans and run a cable back to the PCIe slots ala ribbion style and keep them outside of the case.
Beware of the 6990 Crossfire drifters. Those players will edge the LXE users out a little.
During beta I logged about 2.4 gig of 3 used on each card in some of the hottest fights. I simply established a very aggressive fan profile to stay on top of the heat. That means about 4.5 of 6 availible SLI video ram was consumed often.
One way MSI could improve the LXE is to use Copper all the way through, the fins and all. Not just the pipes.