> * SoC: A5X was 165mm^2. A6X was 123mm^2. A7 is only 102mm^2 with a 64-bit memory interface instead of 128-bit.
This was pretty inevitable; the A5X was _absurdly_ large for a mobile SoC, and they only did it because they had to. Even the A7 is on the hefty side; it's about the biggest of its process node.
* SoC: A5X was 165mm^2. A6X was 123mm^2. A7 is only 102mm^2 with a 64-bit memory interface instead of 128-bit. They can do PoP memory too for even smaller PCB area. So much cheaper. * WiFi/LTE: same chips probably used on iPhone 5c, 5s, iPad Air, and iPad mini. Simpler inventory and buy in even higher quantities. * Screen: same screen as all previous retina generations likely. * Battery: much smaller since the GPU is more efficient. More cost savings.