It's not totally clear to me if the M1 gains are from the 5nm process, which even AMD hasn't transitioned too yet while still smoking everything Intel on 7nm, from ARM itself, or from some mix of both.
Of course, it's probably a mix, but I don't know if ARM alone has much in that mix. It does seem to me that, even if ARM held no performance benefit over x86, Apple would still decide to use it based on their use of it in their hugely successful mobile products.
I think M1's gains are mainly from the specific configuration they chose to build the ARMs in (after doing the necessary quantitative analyses), not from actual development of CPU tech.
When the first chips using Apple's Firestorm cores were announced on 5nm, the theory was that Apple had used the node shrink to decrease power usage, not increase performance.
>The one explanation and theory I have is that Apple might have finally pulled back on their excessive peak power draw at the maximum performance states of the CPUs and GPUs, and thus peak performance wouldn’t have seen such a large jump this generation, but favour more sustainable thermal figures.
Apple’s A12 and A13 chips were large performance upgrades both on the side of the CPU and GPU, however one criticism I had made of the company’s designs is that they both increased the power draw beyond what was usually sustainable in a mobile thermal envelope. This meant that while the designs had amazing peak performance figures, the chips were unable to sustain them for prolonged periods beyond 2-3 minutes. Keeping that in mind, the devices throttled to performance levels that were still ahead of the competition, leaving Apple in a leadership position in terms of efficiency.
Of course, it's probably a mix, but I don't know if ARM alone has much in that mix. It does seem to me that, even if ARM held no performance benefit over x86, Apple would still decide to use it based on their use of it in their hugely successful mobile products.