Rumors are floating around that the 790GX will support CrossfireX (not full speed but half speed two x8 slots) as well as Hybrid Crossfire to reduce power consumption and boost performance when teamed up with a discrete graphics card such as the Radeon HD 3450.
This chipset could spell trouble for Nvidia who has only just launched its new AMD based chipsets (750a and 780a). You will just have to wait and see till the reviews come out in May.
You can probably expect to see many ODM based 790GX boards on display at Computex Taipei 2008 in June.