Where does this memetic lie come from?
AMD's listed "15W TDP" is irrelevant to the observed wattage and frequency (or performance) curves.
And we've seen Apple's A12, A13 on a similar TSMC 7NM node - older if I may add so AMD garners what little improvements are made on that process since then.
Here's a fairly telling chart on the performance: watt curves. https://hexus.net/media/uploaded/2020/8/f5957fa8-630f-44be-b...
BTW: it doesn't improve too much on Zen 3. Slope is just not ARM, much less Apple-tier.
Inevitably someone will chime in and point out AMD's power efficiency is subpar due to boosting far beyond optimal points on the curve; while true this is inefficient we can truncate their frequency to Apple's 3.2GHZ or merely observe the slope of the p:w curves above - at almost any point on the y axis, an A12 or A13 will be taking AMD to the woodshed on performance per watt. And I'm not exactly amicable to handicapping the comparisons by giving AMD & X86 a half decade to work out the architecture before things are "fair". As it stands, Apple's architecture is simply more performant.