NVIDIA's
Optimus Technology is pretty slick. It allows the computer to automatically turn off the discrete graphics card and use the integrated graphics chip to save power. Why use the juice to run the 3D card when all you're doing is reading e-mail or browsing the web? The latest drivers offer up some more customizations for the end user. Yes, the switching does work automatically but if you want more control, here it is for you. Check out the run through on the July update.