I'm trying to make sense of this. When looking into my MBP in the About this Mac> Overview> System Report> Hardware> Graphics/Displays tab it says that their are 2 video cards: Intel HD Graphics 4000; Nvidia geforce GT 650M. No is this something that us built into a MacBook Pro (15-inch, Mid 2012).... or is this a physical device(chip) that you have to install?

MacBook
Pro, OS X Mountain Lion (10.8.2)