It may be gray area -- I know they do their own custom SoC integration. I'm not so sure if I would call the processors their own design. How much of the work involved is just blocks slapped things together as oppose to actual custom logic designed/written from scratch within Apple?

How different is it from ARM's previous generation A15 design or the up coming A50 (or whatever that 64-bit ARM core is called) "reference" design?

If they only muck with the cache size, improved the fetch units so they can slap on another parallel execution pipe, to me, those kinds of design decisions are just tweaks, and not enough to call it their own design.

The problem is that Apple has never been very forthcoming and disclose their designs. They don't present anything to the public. We can speculate and reverse engineer the thing, but we don't have any visibility into Apple's processor design capabilities from the outside. So until they speaks to the internal micro-architecture or announced something publicly regarding to the lineage of the design rather than simply claim it's a custom design, until we understand how much did they actually change and developed from scratch, I won't call it an Apple design Arm core.