Re: Howto Check SLI
Not all programs can take advantage of SLI. It depends a lot on how the program is written. There's an NV-CONTROL option called 'slihud' which shows a bar in OpenGL apps showing how the load is divided between BOTH GPUs. The option is only available in case of SLI (so using that you can already see if it is on) and it allows you to see how much SLI helps for this game.
I'm not sure if nvidia-settings supports this option else use nvclock which can set it for sure (you need 0.8 beta2 of nvclock).