To use NVIDIA SLI technology with one SLI card
You cannot use NVIDIA SLI technology with only one SLI-ready NVIDIA GPU-based card.
However, if you are able to access the Set SLI Configuration page from the 3D Settings page, this means that you are running on a computer that is SLI-ready and it has at least one NVIDIA GPU-based SLI card installed. You can choose to add a second such card for full SLI functionality and view amazing improvements in the rendering performance of your Direct3D and OpenGL application content.
If you want to add a second SLI-ready graphics card, do the following:
Shut down your computer.
Add a second NVIDIA GPU-based SLI-ready graphics card to your system using the instructions that came with your NVIDIA SLI graphics card package.
Turn on your computer.
Right click on your desktop and select NVIDIA Control Panel to open the Home page.
See the topics under "Related topics" below