看了這網頁
http://www.nvidia.com/object/3D_Vis...Technology.html

Powered by NVIDIA SLI Technology
> NVIDIA Surround technology requires multiple NVIDIA GeForce
GPUs to drive high definition gaming across three monitors
> Only GeForce GTX 400 GPUs deliver the graphics horsepower
needed to power 3x Full HD 1080p 3D displays for an incredible 5760x1080 3D experience (over 750 million pixels/second)

SLI 技術這邊才提到可使用3螢幕

也可以看一下詳解(簡體)
http://www.expreview.com/9394.html