This isn't a rumour, it has also been tested by Gamers Nexus:
Article here: https://www.gamersnexus.net/guides/3...-duration-z390
Video included in the article:
The real problem at the end of the day is that Intel wants to have their cake and eat it. They are not willing to admit that the 9900K is in fact a ~150w TDP CPU, and that's not counting using the iGPU at the same time, at which point it's probably more 170w.
Also, with the limits enforced, you get inconsistent performance as it will only boost to 4.7 Ghz on all cores for 100 seconds, which is great to produce misleading benchmarks that only last up to that long, to present to the public, as TechSpot alludes to at the end of the article. This is basically Intel employing one of the tricks that CPU makers use for mobile CPUs to deal with power/temps/chassis constraints in laptops, except we're talking about a high-end mainstream desktop part here.
Further problem, with the limits enforced, after 100 seconds you get an all core boost of around 4 Ghz. The Ryzen 7 2700X gets to an all core boost of around 4.1 Ghz with a good cooler. See the problem? How can Intel justify charging so much for the 9900K if the difference in performance would be much lower compared to the competition?
Intel has to prove that they are not being complicit with this situation and enforce their own guidelines with motherboard manufacturers ASAP. Who is responsible for running chips out of spec in this situation anyway? This is a mess even from that standpoint. Which company is going to handle warranties if things go bad?
Ideally they should raise the TDP of this chip to 150w - 170w and get rid of the inconsistent performance and the obfuscation that is the PL2 parameter, but they probably don't want to assume that responsibility with lower end boards in the mix, chip variability, temperatures, etc, so we're left with these tricks. The consumers end up losing here.