The main advantage that you get between the 890GX and 790FX chipsets is that with the 890GX comes the SB850 southbridge which has native SATA3. The 790FX chipset, on the other hand, is geared towards people who intend to Crossfire some big cards. With the FX series boards you get the full dual x16 experience. With 890GX going dual means an x8/x8 crossfire. It doesn’t have the same bandwidth in the PCIe lanes. Of course, the FX board is only worth it if you intend to crossfire some pretty heavy duty cards in dual, or perhaps crossfire 3 or 4 cards (x16/x8/x8 or x8/x8/x8/x8). So you’ll have to judge just how ambitious your graphics set up is going to be.