There's an anecdote from Jim Keller that Zen is so modular that it'd be possible to swap out the x86 instruction decode block with an ARM one with relatively little effort. He's also been saying for a while now that ISA has little bearing on performance and efficiency anymore.
Apple's decision to switch to ARM had many reasons, licensing being just as important as performance, perhaps more so.
The low power variants of Zen are very efficient. You're still looking at Intel, but they've been leapfrogged by AMD on most fronts over the past half decade (still not market share, but Intel still has their fabrication advantage).
I'll believe that when I see a Zen-based phone with a non-awful battery life. Yes AMD are ahead of Intel in some areas, but they've got the same vested interest in talking up how power-efficient their x86 cores can be that may not actually be based in reality.
You won't see that happen because AMD have no interest in targeting phones. Why bother? Margins are thin, one of x86's biggest advantages is binary backwards compatibility but that's mostly meaningless on Android, there's additional IP and regulatory pain points like integration of cellular modems.
Intel tried and ran into most of those same problems. Their Atom-based SoCs were pretty competitive with ARM chips of the day, it was the reliance on an external modem, friction with x86 on Android and a brutally competitive landscape that resulted in their failure.
Regardless of architectural advantages from one vendor or another, the point remains that the arguable preeminent expert in CPU architecture believes that ISA makes little difference and given their employment history it's hard to make the argument of bias.
> Intel tried and ran into most of those same problems. Their Atom-based SoCs were pretty competitive with ARM chips of the day, it was the reliance on an external modem, friction with x86 on Android and a brutally competitive landscape that resulted in their failure.
The way I remember it the performance and battery life never quite lived up to what they said it would.
> Regardless of architectural advantages from one vendor or another, the point remains that the arguable preeminent expert in CPU architecture believes that ISA makes little difference and given their employment history it's hard to make the argument of bias.
Current employer is a much heavier influence than prior employers, and someone who's moved around and designed for multiple ISAs and presumably likes doing so has a vested interest in claiming that any ISA can be used for any use case.
There's a long history of people claiming architecture X can be used effectively for purpose Y and then failing to actually deliver that. So I'm sticking to "I'll believe it when I'll see it".
Apple's decision to switch to ARM had many reasons, licensing being just as important as performance, perhaps more so.
The low power variants of Zen are very efficient. You're still looking at Intel, but they've been leapfrogged by AMD on most fronts over the past half decade (still not market share, but Intel still has their fabrication advantage).