Hardware

Awesome video! I’d never even thought about x86 applications using native Arm libraries but it makes sense.

Interesting topic, but tragically shallow treatment of the subject. He tested with Handbrake and found Apple's Rosetta 2 to be slightly better (lower overhead) than Microsoft's solution, and tested with some of his own code and found Microsoft's to be significantly better than Apple's. But we didn't get any description of what that mystery code is doing, so it's a largely worthless result and leaves him without enough justification to make any solid conclusions (Handbrake is a good test to start with, but not enough on its own).

I would have liked to see a comparison of what x86 instruction set extensions are supported by the respective compatibility layers (especially the SIMD extensions), an overview of the general techniques used by the compatibility layers (ie. ahead-of-time translation or JIT or instruction-by-instruction emulation or a mix of techniques) and how much caching of translations affects first-run performance vs subsequent runs, and comparison of both single-threaded and multi-threaded workloads (because ARM's weaker memory model than x86 is a major challenge for translating multi-threaded code with low overhead).

This video entirely misses the point. The x86 emulator (technically a transpiler) is just a part of equation. The important thing is that Apple emulates some of the x86 behavior in hardware. And it’s not something a software emulator can do, at least not without significant performance problems. As far as I know, current Windows on ARM ”cheats” by pretending memory order is not a problem. This works until it doesn’t, as some software will crash or produce incorrect results. Microsoft has different emulation levels as described in their support docs, each with those come with increasing performance cost. As Qualcomm did not announce technology to safely emulate x86, I assume they don’t have it. Which would mean the same clusterfuck of crashing and incompatible software Windows on ARM has to deal with now.

https://learn.microsoft.com/en-us/windows/arm/apps-on-arm-program-compat-troubleshooter

Windows emulation is less likely to get rugpulled out from under your feet by Microsoft, whereas history show Apple will do just that in a few years and remove the translation layer to mess with people/devs ('cattle loses discipline without flogging' Apple style).

So I'd say it wins on that ground.