The 5800X is an outlier among Zen3 though - while the 5900X and 5950X have higher single core power draws,
the 5800X matches or exceeds their per-core draw from 6-8 cores. Yet it clocks lower. This likely means that the 5800X is a relatively different bin from both the 5600X and 59xxX chips, one where power consumption under high loads is less important - simply because it has more room to move with a 105W/138W power budget and just one CCD. Literally every other Zen3 product out there would do better in that comparison against the 10900K. Which, of course, ignores the 10900K having a 2c4t advantage. So, Intel gets the inherent efficiency advantage of being "wide and slow" compared to AMD's somewhat low binned, high clocked 5800X, and still only matches them? That's not a particularly impressive showing.
Is this the review you're referring to, btw? I can't find that they say the 12900K is generally more efficient than the 5950X there - in that (
extremely unreadable) graph of theirs they seem to both take the lead in various tests. I have no idea which of them are ST and which are MT, though. I have seen ST tests where AMD comes out looking decent in terms of efficiency against ADL, but sadly I can't remember where - and even more sadly, most reviewers limit their efficiency testing to one or two scenarios, which really limits results.
Yeah, it's still a very efficient architecture - it's just getting to a point where the higher power floor of package-based IF is starting to show its weaknesses.