I think i will go back to windows 7 as windows 8 can't detect the 4 core of AMD A10-5700 but other software can detect the four cores. Maybe a bug for windows 8. 
It's really just how the software sees it, and that is because of the bulldozer/piledriver architecture. The same thing is true for FX processors. Windows 8 is supposedly beneficial for these processors because it is aware of the design and schedules threads better because of this.
Here's a screen cap from an FX:
There might be a patch/update that would make this show differently, but Windows would still handle scheduling the same way because it generally works better this way. Windows 7 originally handled each Bulldozer module as 2 cores, and that resulted to diminished performance. Later scheduling updates allowed Windows 7 to "recognize" the design by allocating to fewer modules and maximum logical cores per module for turbo boost advantages, and spreading to multiple modules and minimum logical cores per module for parallel performance. Windows 8 goes a little further with some more scheduler optimizations. In the real world, the performance improvement has been quite small however (lack of thorough optimization from both the OS and current applications) -- the original FX patches improved Windows 7 performance by about 3%, whilst Windows 8 is about 2% faster on top of that.
I can discuss it in detail if you want to, but the bottom line is that by seeing your APU as a 4-thread 2-core processor, Windows can split loads between the modules better (instead of taxing one side and under-utilizing the other) if you need to, and put all the load on a single module if turbo frequency or improved power consumption/thermals is desired.
