You've never had to rub a bag of frozen peas all over the bottom of your x86 Macbook Pro because it was overheating and you had an imminent zoom meeting you could not miss.
Those chips were designed and fabbed by Intel, not by Apple/TSMC respectively. That’s the relevant difference, not the instruction set.
The instruction set has only moderate impact on the chip’s frontend, and no impact on the backend. Most design decisions are unconstrained by the choice of instruction set.
The last few generations of x86 MacBooks were exceptionally bad implementations in this regard, and some of the better thermal behavior of the Apple Silicon MacBooks are things that they could just as easily done with an Intel CPU, if they had felt like it. For example, the Intel MacBooks was extremely eager to ramp its power consumption to the max, while the ARM MacBook slowly increases clock rate, one step at a time, such that it only hits max power after a long time of sustained demand.
I think that might have been Intels doing. They were on 14nm for 5 years or so, with each new 14nm release pushing the power budget and squeezing slightly more performance out of any corner they could find. I assume the CPU ramping was just another part of this approach. If the CPU ramps up faster it will seem fast to users and it’ll look faster in short benchmarks like Geekbench.
AMD doesn’t have that problem, though, so is it a problem with x86 or Intel? I would bet that Apple’s CPU team could get great results with a free hand on x86, too – probably not quite as good but close.
