Quad-SLI technology works correctly, but its performance scalability is poor, as opposed to that of the Radeon X1950 XTX CrossFire. The latter outperforms the single Radeon X1950 XTX by 40% in 1920x1200, which is a good, although not perfect, result.
ATI’s and Nvidia’s solutions are equals when we enable SLI AA and Super AA. ATI wins the low resolutions, but the GeForce 7950 quad-SLI system is superior in 1920x1200.
The GeForce 7950 quad SLI slows down after we turn on 16x SLI AA. The game speed is below comfortable even in 1280x1024. And on the contrary, the Radeon X1950 XTX CrossFire switches from 8x to 14x Super AA easily enough and only lacks speed in 1920x1200 resolution.