AnandTech adds SLI-AA benchmarks to ASUS A8N3-SLI Deluxe review
 

NVIDIA introduced special SLI-AA Modes beginning with driver version 77.7x. By running Coolbits, selecting "Advanced Settings" under "View" in the "Performance & Quality Settings" area, and selecting "SLI-Antialiasing" under the "SLI Rendering Mode", you have new options to run games at 16xAA or 8xAA independent of application control. There are many potential advantages to SLI-AA mode. You can find more information on how this feature works and the potential benefits at NVIDIA Announces 16x AA For SLI.

http://www.anandtech.com/mb/showdoc.aspx?i=2589&p=11

As you clearly see from the test results we did not find ANY performance improvement in either SLI-AA mode on the Dual x16 board compared to the Dual x8.

what a surprise:)

SLI32 : fine example of modern marketing tricks in my humble opinion