Hi,
IF you already have an A8 then look at some benchmarks or the hundred of youtube videos in this config. Essentially the Hd6670 is doing all the work. Adding an HD6770 would give higher gaming performance even though it wouldn't xfire.
IF you don
t have the A8 already and if you know that you are adding a video card then A8 is not a good CPU choice. You can do better for the same money with a stronger CPU and stand alone video card.
From:
http://www.overclock3d.net/reviews/cpu_mainboard/amd_a8-3870k_black_edition_hybrid_crossfire_review/9
"... it's difficult to see why you'd choose this model over any others. ... for about twenty pounds less you can retain your AM3 motherboard and grab a Phenom II X4 965. The other limitation is the small selection of GPUs that support the Hybrid-Crossfire. They're all underpowered and overpriced and there are much more powerful options available for around the same money. So although Hybrid-Crossfire is an option, it's not one that makes sense because if you're going to have to buy a GPU you might as well get a better GPU and a better pure CPU to go alongside it, even if you insist on sticking with AMD.
"So this has a very small target audience of people who just want a CPU that is a decent performer that will cope with most home tasks without breaking a sweat and has a decent integrated graphics chip for some light gaming at medium resolutions. To these people it's definitely great value for money.