Too much here for a multi-quote. The APU scales just fine when overclocked. I got an A6-3650 up to 3.64 GHz stable. That is a full 1 GHz overclock (38.5% OC). I got the A8-3850 to 3.53 GHz stable using a GIGABYTE UD2H. Dave got a A8-3850 up to 3.7 GHz I think using the UD4H. For how this affects performance: http://www.futurelooks.com/amd-llano...level-pc-king/
The GPU doesn't need to be unlocked as you can change it anywhere from 200 MHz to 2 GHz core. It is pointless to go over 600 MHz if your RAM is 1866 MHz or below as the RAM will limit performance long before the additional core speed will.
And the bclk change only limits overclock on boards with no automatic dividers like Biostar and ECS. The GIGABYTE boards seem to have a huge advantage in overclocking locked APUs. These "K" APUs will level the playing field in this regard.