AMD could enter ARM market with Sound Wave APU built on TSMC 3nm process

Better (or simply more) ARM processors, no matter who makes them, are a win. They tend to be far more power-efficient, and with performance-per-watt improving each generation, pushing for wider ARM adoption is a practical step toward lowering overall energy consumption.

Are ARM processors inherently power efficient? I doubt.

Performance per watt is increasing due to the lithography.

Also, Devon’s paradox.

They aren't inherently power efficient because of technical reasons, but because of design culture reasons.

Traditionally x86 has been built powerful and power hungry and then designers scaled the chips down whereas it's the opposite for ARM.

For whatever reason, this also makes it possible to get much bigger YoY performance gains in ARM. The Apple M4 is a mature design[0] and yet a year later the M5 is CPU +15% GPU +30% memory bandwidth +28%.

The Snapdragon Elite X series is showing a similar trajectory.

So Jim Keller ended up being wrong that ISA doesn't matter. Its just that it's the people in the ISA that matter, not the silicon.

[0] its design traces all the way back to the A12 from 2018, and in some fundamental ways even to the A10 from 2016.

As far as I know people aren't part of ISA :)

People are absolutely part of an ISA's ecosystem. The ISA is the interface between code and CPU, but the code is generally emitted by compilers, and executed in the context of runtimes and operating systems, all designed by people and ultimately dependent on their knowledge of and engagement with the ISA. And for hot code in high-performance applications, people will still be writing directly in assembler directly to the ISA.

ISA != ISAs ecosystem

ISA is just ISA