[emn13]

Manufacturing process definitely impacts transistor performance including critical things like leakage and speed/voltage trade-offs. I'd be quite surprised if benchmarks that included power consumption couldn't distinguish between the two sources. As to whether it's going to be noticeable in practice - who knows, but the fact that apple's risking it suggests they're confident enough.

Similarly, I'm not sure how you expect reliability not to be affected by process; of course it'll be. But how often have you heard of a chip failing after it passes initial validation (something presumably apple does have a hand in)? It's not going to matter.

[gothenburg]

Just a note before anything else: it's not a "manufacturing process". Nobody is laying out the transistor by hand, it's a fabrication process. (I apologize for nitpicking in the wording, but it's important)

Apple does these kind of things for two main reasons: Because they have the money and because they want to test both fabrication processes for future products

The differences between a 14nm process and a 16nm process are quite minimal mostly because one process can offer some advantages over the other one. For example: it's expected that the smaller process has bigger leakage current, increasing power consumption, while it's expected for the bigger process to produce more heat.

In the end, you could say that if you sum the advantages and disadvantages of both, you will not reach any conclusion if you are not the engineering team looking for extreme optimization and with Apple's resources at your disposal.

It's just hard to come to a concrete conclusion from a consumer's point of view.

[emn13]

It's not just 14nm vs. 16nm though - two 16nm processes can still have significant differences due to materials

And even "16nm" something of a marketing term - something tiny feature in there is at 16nm resolution, but lots of other things are larger. And which things are how large, of course, also matters...

[shalmanese]

You can't have one process consume more power and the other process produce more heat. Power is converted to heat at 100% efficiency so more heat must mean more power.