The problem with devices that add more power to your machine is that they also tend to suck a lot of juice. In the case of laptops, you want to be able to squeeze the most life out of your battery as possible. A new technology from Nvidia will give you the best of both worlds.
They are calling this new technology Hybrid SLI, it works in notebooks that feature their own integrated graphics processor and discrete GPUs. When you are not running graphic-intensive applications, it will disable the discrete GPU and only run off of the Nvidia IGP. It will automatically switch back to the discrete GPU when needed.
This will allow the computer to draw less power, and in the case of notebooks, allow for longer battery life. The technology is expected to show up in both desktop and laptop PCs sometime around the end of the year.
Nvidia plans Hybrid SLI technology [via digitimes]