If Overclocking ability is an isue, the Ocing capability for micro boards in general pales in comparison to a full featured enthusiast oriented MB. 780/785 are micro boards with 'limited' overclocking ability. My ASUS 780G onboard 3200 is 'OK', but weak and not overclockable at all with ATI drivers.
780G has native crossfire which I use. The onboard 3200 in Xfire with a Radeon 3450. It's weak. Apparently the 785G doesn't offer native crossfire. I used the onboard 3200 chip briefly before I added the 3450 in Xfire. In Xfire the 3450 is Overclockable, but not the 3200 onboard. In addition, I have not read any reviews concerning the 785G onboard. The 3200 onboard gets good reviews. At any rate, the onboard chips perform miserably when compared to say, the 3870 I had installed briefly on my 780G. I wanted a quiet, low power machine not a gaming setup so I went back to the 3200/3450 xfire set up for now.