yes, but if the 7945HX3D is running at 112W (75W cTDP + AMD allows unlimited-duration boost at 50% above this) and the macbook is running at 50W cpu-only (70W TDP) then the macbook is actually substantially more efficient in this comparison.
That's why I said: you have to look at the actual power measurement and not just the box spec, because Apple generally undershoots the box-spec for cpu-only tasks, and AMD always exceeds it substantially due to boost. Obviously if you give the AMD processor twice the power it's going to be competitive, that's not even in question here. The claim was, more efficient than Apple - and you simply cannot assess that with the box TDPs, or even cTDPs, because x86 processors make a mockery of the entire concept of TDP nowadays.
(and it didn't use to be like that - 5820K and 6700K would boost to full turbo under an AVX2 all-core load within the rated TDP! The "boost power is not the same thing as TDP" didn't come around until Ryzen/Coffee Lake era - accompanied by ploppy like "electrical watts are not thermal watts" etc)
edit: notebookcheck has cinebench R15 at 36.7 pt/w for M3 Max and 33.2 pt/w for 7840HS, and 28 pt/w for Pro 7840HS (probably a higher-cTDP configuration). Obviously CB R15 is miserably old as a media benchmark, but perhaps ironically it might be old enough that it's actually flipped around to being more representative for non-avx workloads lol.
CB24 MT at 50% higher for M3 Max and CB R23 at 11% higher (shows the problem there with x86 processors on R23). Looking back at Anthony's review-aggregator thing... they're using the highest score for 7840HS I would assume (it's 1k points higher than median on notebookcheck) and also they're probably comparing box TDPs, which is where the inversion comes from here (from parity to a 10%-ish lead on efficiency). Because actual measurements of the M3 Max, from actual reviewers, have CB 2024 at around 51W all-core, and it almost doubles a 7840HS's score there.
And looking at it a little further even that nanoreview aggregator thing doesn't claim 7840HS is more efficient... they rate the M3 Max as being 16% more efficient. Seems that is a claim Anthony is imputing based on, as I said, box TDP...
edit: I’m also not even sure that nanoreview article has the right TDPs for either of them in the first place…
Gamer Nexus has several videos on the topic around PBO and Eco mode.