How many monitors does an NVIDIA® GeForce 7800 SLI system support?
With SLI enabled you will only be able to support one monitor as standard. If you disable SLI in your display properties you are able to connect up to four monitors to the two cards. If you intend to run more than one monitor and want similar performance to SLI we would recommend you purchase a single ATI Radeon X1900XTX card. This will support two monitors (either x2 DVD-I, x1 DVD-I + x1 VGA or x2 VGA).