It's also got a higher core MIPS, seeing as the old nomenclature of AMD (HD xxxx) had x6xx pinned below what nVidia called x40, in the same year. But these aren't even the same year, and, if I remember correctly, the 8670 is one of the 8000-series GPUs that was just a 7000-series GPU with a bigger number and lower power consumption. Might be wrong on that, though, don't know too much about 8000.
in a perfect world we would all be piles of sand with no ability to form coherent bodies of body