As far as I know, K-series parts don't support binning of individual cores- if you have one bad core that'll only hit 5.0, 1-core turbo to 5.1 will still result in the OS scheduler periodically picking that core to use, it clocking up to 5.1, and problems resulting.

Might be wrong, though.

Intel's Turbo Boost 3.0 [1] was their attempt to take advantage of the fact that some cores on a chip can clock higher than others. It does not work well in practice, because it requires too much collaboration with motherboard and OS vendors. This feature is not available on their desktop platform, which the i9-9900KS uses.

[1] https://www.intel.com/content/www/us/en/architecture-and-tec...