Nah, I think he's incorrect. The reason being that the W-2135 is only 6(12) cores, where the W-2140b and W-2145 are 8(16), and the W-2150b and W-2155 are 10(20). However, I would expect that the W-2145/W-2155 would be better than the W-2140b/W-2150b respectively or why not name the cpu the same (or to even differentiate that it was mac-only with just the b)? So the higher clock speed for the W-2145 and W-2155 makes sense, they have similar turbo freqencies (also with the W-2135 but it has less cores, specifically the third number multiplied by 2 is the core count). Comparing the W-2170b and W-2175, or the W-2191b and W-2195, they are the exact same it appears (though I have a feeling they are not because again why would they make two different versions of the same chip with just a different identifier?). The models then all get slower as the identifier increases as the TDP stays the same (140W) but the core counts increase, meaning there is less power for each core. The thing to note is that all of the mac-only models were announced in june of 2017 when they introduced the imacpro, but weren't released until the imacpros actually came out in december. The other models were announced and released all on the same day in august 2017. This is actually probably a misleading thing though, as most likely the mac-only models were engineered first, much sooner than june and shipped to apple because they then needed to build the imacpro, which needed to be ready by june (because that's when they announced and showed it) but weren't actually released until december. So I think they had the chips already at that point in june, putting the manufacture date at the very beginning of 2017 or end of 2016. Why does intel then wait until august 2017 to announce the consumer available w series, only as the series is released? They probably weren't engineered until early-mid 2017. I would think that the mac-only models are actually probably the specs apple wanted and the others are what intel thought consumers would buy at specific price points after having engineered the models for apple, not wanting to waste a process as they could sell more commercially than to apple alone (not to mention they probably get more money from consumers than from apple per cpu). You can also look that they did not release any W-216X or W-218X cpus (which would be 12 and 16 cores and no other models in the W series have those core counts). Why also name the one randomly W-2191b when the other mac-only models end in 0? Maybe they intended to release those models but ended up changing their minds and there would have been a W-2190 which would be slower than the W-2191b (or maybe they still may release them). After reading what he says in his post, he even appears to state a better reason than heat for the difference, they actually are different and have integrated graphics. Then he states the integrated graphics are disabled by the OS, more implication here on my part, but I imagine this is what is causing the issues. On a mac, the integrated graphics are initialized by the firmware but then disabled by the OS, this is perfectly acceptable. On non macs, the integrated graphics are not initialized but then the OS tries to disable the integrated graphics, this is an issue, especially when there is no integrated graphics (not using a mac-only model). The firmware for C422 probably doesn't even attempt to initialized integrated graphics because well it doesn't actually support integrated graphics (https://ark.intel.com/content/www/us/en/ark/products/126691/intel-c422-chipset.html). This is an interesting read (https://www.pcgamer.com/heres-what-you-need-to-know-about-kaby-lake-x/), maybe the mac-only models are actually re-purposed skylake cores with integrated graphics as well that can't actually work because of the C422 chipset not supporting integrated graphics. I wonder if the other models are actually a different process then or not... Lots of information here, and some speculation..... I think you have discovered you have two ways to configure to get working system and power management with the w series, fakecpuid + patch _xcpm_pkg_scope_msrs, or bootstrap patch + frequency vectors.
EDIT: Oops, I meant skylake for the w series, not kaby lake, lol.