TL;DR: The A16 SoC that will be used on the iPhone 14 will probably not bring massive performance and efficiency gains if it's going to use the same process as the A15 Bionic. Apple will reportedly rely on architecture improvements and a switch to LPDDR5 memory and use the new chip only in their iPhone Pro series.
In a series of tweets today, analyst Ming-Chi Kuo indicated that Apple's upcoming A16 chipset might continue to use TSMC's N5P process node, the same as its predecessor, the A15. The decision was reportedly made because the Taiwanese foundry won't be able to produce enough chips on the new N3 node this year to fulfill demand. Meanwhile, N4P, another improved variant of the N5 process, will only start mass production next year.
This leaves Apple with a choice between N4 and N5P, with the latter being the better-performing (and probably more expensive) node. It's unlikely that the company will switch over to Samsung's GAAFET 3 nm process, as the last A-series chip that wasn't manufactured exclusively by TSMC was the A9, which came out in 2015.
(1/4)— 郭明錤 (Ming-Chi Kuo) (@mingchikuo) May 29, 2022
According to TSMC's public announcements & the roadmap (source: https://t.co/EgzC8D1Wys):
1. Significantly better N3 & N4P won't start mass production until 2023.
2. N5P & N4 are the latest technologies Apple can use for 2H22 products.
3. N4 has no advantages vs. N5P. https://t.co/k3OCX5EqjJ pic.twitter.com/kmzQEyxRkN
As a reminder, Apple is expected to only equip higher-end iPhone 14 Pro models with the new chip, with the vanilla phones shipping with the A15 instead.
Kuo also reiterated that the upcoming MacBook Air refresh might keep using the M1 chip instead of launching with the new M2. The laptop is rumored to come with an all-new design, something Apple seems to believe is a much better selling point than new internals (and we tend to agree, the M1 is pretty good in terms of efficiency).
The Cupertino company would opt to debut the M2 SoC next year on a MacBook Pro lineup update. This would also allow them to take advantage of the more advanced N4P or N3 node.