Hothardware published a test report of the Quad-SLI configuration of the new NVIDIA 9800 GX2 and nForce 790i SLI Ultra chipset.

Quote from the review: "Last week, NVIDIA formally launched the dual-GPU powered GeForce 9800 GX2 graphics card and nForce 790i SLI Ultra chipset. We evaluated both products in our coverage of the launch, but had to leave out one important detail per NVIDIA's embargo agreement - that being Quad-SLI.
The embargo has since lifted, however, and today we take a look at 2008's version of Quad-SLI technology with a pair of retail-ready graphics cards from ASUS, the EN9800GX2. Head on over to the site for the full scoop..."
Read the full review on Hothardware. Buy the newest Graphics Cards on NewEgg.