I use sli , 2 screens both at 1920 x 1080 and I get between 50 and 100 frames . I get occasional cloud flicker but only occasional so I cannot complain. With one card and ONE screen I get the same fps but as soon as I add a second monitor I drop to 50 on average with one screen. Soooo, if you want multiple monitors then sli IS worth it to have the game running at such a high frame rate, sli is commonly disregarded and I have no idea why because it gives me high frames, higher frames and a second monitor to use as a targeting pod.