Switchable graphics: Discrete AND integrated in one?

[Novi]

If I understand this correctly, the models with a discrete graphics card also have the Intel GMA4500 chip in them? So you switch between those two? Or do the discrete ones have some other integrated solution?

[Dead1nside]

The integrated graphics are in the chipset and the discrete model also uses the same chipset but also has a discrete ATI graphics card. One apparently can switch, without rebooting, by clicking a button in Power Manager.