It's my understanding that when you get an APU, which is a combined CPU and Graphics chip you are forced to Crossfire only with the same graphics chip, unlike a normal computer where the CPU is by itself or the graphics can be disabled.
Micro-stutter is an issue with Crossfire (and SLI) and is worse with two, low-end cards.
Micro-stutter is LESSENED if you have a 3x Crossfire situation (APU + two graphics cards).
*Having said that, there's a price point at which it makes sense to rip out the APU in favour of a regular CPU and a good, single graphics card.