At the heart of the MobileMedia platform is Nvidia's GeForce 5500 chip, which supposedly delivers "console-class 3D gaming, " although they convienently don't specify which console -- we're guessing it falls somewhere below an Xbox 360 but above a Sega Genesis.
Remember: your brand new Wii U can do literally nothing outside of build Miis and play disc-based games before the update, so don't go freaking out when your console seems to be missing a few key functions out of the box.