The Tech Report writes motherboards with the AMD 790GX chipsets will have integrated graphics and a new type of hybrid CrossFire:
The mobo includes an onboard memory module next to the north bridge, foreboding the presence of an integrated graphics core.
Meanwhile, Fudzilla plainly states that the 790GX chipset will introduce a new type of hybrid CrossFire mode that will couple a pair of discrete graphics cards with an integrated GPU. Fudzilla doesn't mention any power-saving tricks, but such a chipset would be ideal for a feature akin to Nvidia's HybridPower.
For those not in the know, HybridPower involves plugging one's monitor into the IGP, then having the chipset tap into discrete graphics processors as needed, switching them off when the user isn't running any games or 3D applications.