It is simply a mystery how Apple and Samsung could be competitors and best of customers. You have Samsung make A7 chip which is there to knock-out Samsung products in the market. A unique case for business schools.
Noticed denser interconnects in the A7, perhaps to accommodate the 2x wider ( 64 bit ) data and address buses within more or less the same real estate. Chipworks could go back and take one more look at their teardown of the Exynos 5 ( 32 bit 8 core ) in the Samsung S4 phone and compare the interconnect w/ the A7 ( both 28 nm by Sam ). Performance can actually take a hit if interconnect conductors & dielectrics are shrunk too much since resistance & capacitance will go up and will become a larger factor as the transistors get faster & more efficient.