I guess it would be personal preference
in my case, the only CPU with on die graphics is my i7-2600k, in which I have it disabled, to where all video / graphics is coming from my dedicated video card
If it was me, I would disable it for your AMD CPU/on die GPU graphics............... but what it does is use the on die integrated HD3000 chip for graphics that don't require a lot of power/performance, then should turn it over to your dedicated HD6950 video card when it needs it for like Aces High or other Games, graphic intensive programs, etc.......
easiest/simpliest way I can explain it
EDIT: you posted that the HD3000 is integrated on the MB, I mistook it for being built in die on your CPU processor ( like my Intel CPU )..... if it is integrated into the Motherboard itself, then I would definitely disable it, and I would disable it in the bios, instead of doing it through device manager............. YMMV
hope this helps
TC