I just got 2 GTX 560 TI's for christmas and added them to my system, now my CPU is a phenom II 965 Black Edition Over Clocked to 3.9 GHZ. I have 8 gigs of ram and a m3n-HT Deluxe motherboard. My FPS is about the same in SLI and when it isn't, now I figure I might be bottle necking my system but I am not sure. I figure that 3.9 GHZ on a quad core system could handle the 2 video cards but am I wrong or just missing something?
Yes, I have the annoying little sli bar to even tell me it is working. Left for dead 2 hovers at almost the same exact FPS in the same parts of levels with it enabled as when it isn't. In Furmark 1.9.2 I get 617 score while using 1 video card and 574 with SLI enabled.
I have been hearing that the 1.9.x versions of furmark are buggy and not giving accurate numbers so I downloaded the 1.8.5 version just now and I went from a score of 4187 in single gpu mode to 8628 in SLI at stock speed. When I Overclocked them to 950 MHZ and 2149 Memory each I got a score of 8846. I am just going to assume that Left for dead 2 doesn't scale well with SLI and that the new Furmark 1.9.x versions are bugged. I will do some more testing later tonight and see for sure.