https://www.cnet.com/news/intel-core-i9-9900k-may-boost-to-5ghz/

The i7-9700K however, will be very close -- it will boost to 4.9GHz on a single core (4.8GHz on two), or 4.6GHz on all cores. The difference is the i7 is dropping hyperthreading, the technology that gives you eight threads on a quad-core processor, for example. At four cores, the most common popular optimization for most software, the i7-9700K boosts to 4.7GHz and the i9-9900K to 4.8GHz. So the gap between the the two processors many not be that large for tasks that don't take advantage of hyperthreading or more cores.

Wccftech found a confirmation of the ninth-gen processors in Intel's microcode update guidance a few weeks ago, but other specs -- and SiSoft Sandra benchmark results for the i7-9700K -- have also surfaced.