Earlier quoted context omitted.
> I believe Intel processors can't boost all cores. And that's exactly what shereadsthenews's point is. They can't boost all cores, and they are not boosting any core beyond the all-core capacity if it's truly a CPU that runs at 5 GHz all the time.
Turbo Boost can certainly apply to all cores- the limits you hit are TDP and time based, there, not strictly thermal. So, for example, my old laptop CPU would clock itself up to 2.7GHz on all cores... well, okay, it was a dual core, so that's not saying much, but still. But it'd only maintain that boost for a few seconds- under sustained load it dropped down to 2.5. This wasn't because of thermals, but rather because…
> As of 3/16/19, the top 38% of tested 9900Ks were able to hit 5.0GHz or greater.
> As of 3/16/19, the top 8% of tested 9900Ks were able to hit 5.1GHz or greater.
So, Intel'd cut their yield by more than a factor of four if they only let parts that could hit 5.1 into this bin. For a 2% single-core performance boost...