AMD's 790GX chipset combines the best of 780G and 790X
According to fudzilla.com the 790X Northbridge will be replaced by the 790GX.
790GX: AMD's new chip supports CrossfireX and Hybrid Crossfire (picture: AMD)
The "G" is take from AMD's 780G and implies that there will be an IGP (integrated graphics processor) included. The 790GX combines the advantages from the 790X and the 780G.
The IGP is said to be called HD 3300, running at 750 MHz clock speed. The supported sideband memory is increased from 64 MB to 128 MB. Furthermore the 790GX is supporting Hybrid Crossfire (X) but won't deliver any performance boost to high-end graphics cards.