> I believe Process has the most to deal with energy efficiency due to the shrinkage, which is why M1 was so energy efficient when it was launched.
Eh, that's part of it, but a lot of it has to do with the M1 having very very high IPC (much higher than comparable x86-64 parts), meaning they could run the chip at a much lower max clock speed (3.2 GHz versus boosting to 5 GHz for most competitive x86-64 CPUs) for similar overall performance.
This makes a huge difference because power consumption increases exponentially with clock speed.
edit: thinking about how it relates to Intel's process–architecture–optimization, it feels a bit tricky to compare. Apple's process seems to be something like: architecture(A-series chip for iPhones)-optimize-with-new-die-reusing-basic-cores-in-diff-arrangement-targetting-perf-in-small-thermal-envelope(M1 for iPad Pro and small Macbooks)-optimize-again-with-another-new-die-reusing-basic-cores-but-in-yet-another-arrangement-targetting-perf-in-a-wider-thermal-envelope(M1 Pro/Max/Ultra), and that all happens before you get to the next M-series increment, which begins with an A-series increment.
So the M2 is less the optimization of the M1 than it is the re-use of the cores in the new A-series chip preceding it, which was an architectural change, plus optimizations and other SoC differences.
I said "power consumption increases exponentially with clock speed" not "power consumption increases exponentially with f". That any modern processor has to crank up V to crank up its clock speed is a given.
Hence, power consumption is exponential with clock speed (which is achieved by cranking up both V - the polynomial term in P – and f).
(Which, fine, if you want to be pedantic, is polynomial growth, but that changes nothing about the point, which is that you have to burn a shitload more power at 5 GHz than at 3.2 GHz, because your consumption isn't scaling anything close to linear).
Eh, that's part of it, but a lot of it has to do with the M1 having very very high IPC (much higher than comparable x86-64 parts), meaning they could run the chip at a much lower max clock speed (3.2 GHz versus boosting to 5 GHz for most competitive x86-64 CPUs) for similar overall performance.
This makes a huge difference because power consumption increases exponentially with clock speed.
edit: thinking about how it relates to Intel's process–architecture–optimization, it feels a bit tricky to compare. Apple's process seems to be something like: architecture(A-series chip for iPhones)-optimize-with-new-die-reusing-basic-cores-in-diff-arrangement-targetting-perf-in-small-thermal-envelope(M1 for iPad Pro and small Macbooks)-optimize-again-with-another-new-die-reusing-basic-cores-but-in-yet-another-arrangement-targetting-perf-in-a-wider-thermal-envelope(M1 Pro/Max/Ultra), and that all happens before you get to the next M-series increment, which begins with an A-series increment.
So the M2 is less the optimization of the M1 than it is the re-use of the cores in the new A-series chip preceding it, which was an architectural change, plus optimizations and other SoC differences.