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Comment by cpgxiii

2 hours ago

> I think you're focusing on the details and missing my broader point - the JIT technique for translation only works to break out of the instruction set lock-in. It does not improve performance, so betting on that instead of super scalar designs is not wise.

> Transmeta’s CPU was not performance competitive and thus had no path to success.

I think you are operating with a bit too much benefit from hindsight. In a very reductive sense, every time someone has tried to make dynamic ISA translation work, they have done so because they believe their ability to implement their "real" ISA will be superior in some way than their ability to implement the external ISA. Obviously many have failed at this, usually when trying more ambitious designs, but less ambitious designs (perhaps most famously the AMD K5 and its descendants) have succeeded.

Apple's case is really quite different, in that unlike Transmeta or Nvidia, they already had several generations of CPU implementations on which to base their decisions prior to the point of announcing the macOS x64->arm64 transition, just as they had several generations of Intel hardware to consider when making the PPC->x86 transition.