This is likely a larger reason for the move than the perf/efficiency. Apple likes to ship "premium" products, which forces them into the premium/high margin pri

This is likely a larger reason for the move than the perf/efficiency. Apple likes to ship "premium" products, which forces them into the premium/high margin price tiers with intel/etc. So they will gain a bit with a product laser focused on its market, but alongside that, they won't be paying the kings ransom intel wants for a couple additional cores, or a couple Mhz boost. So they can simplify the binning into best in class, and good yields for the volume product, and pocket the margins on the best in class product segment rather than giving it all to intel.