Motherboard Diagnostic

How do I know if Im using 2 graphics cards at the same time?

I have 2l Nvidia Geforce 9800 GT graphics cards on a ASUS P6T Deluxe Motherboard, when I go into the DirectC Diagnostic Tool, and go under display, it tells me as If I have 1 graphics card working, is there anyway I can see if I have 2 working or not?, I mean it would be a waste of money for a second one to just be sitting there doing nothing.

Your two 9800GTs are working together as one graphics card in SLI mode. Running two identical nVidia cards in SLI mode combines the two cards’ graphics processing power and increases graphics performance.

You can also set your graphics cards to run independently, so you can hook up to 4 monitors. But the graphics processing power will be limited to what each 9800GT can do on its own.