8700K is 6 cores / 12 threads
9700K is 8 cores / 8 threads
apparently more threads was more beneficial for such benchmarks
PS....now I see a 9900K is in there too which is 8 cores / 16 threads....OK so 8700K beating 9900K is a bit perplexing. However, not perplexing in my initial response between 8700K and 9700K
Games usually gain more FPS when you disable HT/SMT on the CPU. Those threads are not easy to optimize and not suited for game data processing.
8700k is 6 cores so ring bus latency is 20% lower by average. Unless 8700k is limited by its 6 cores throutput, its always better than a Intel 8 core CPU. Same goes for 7700k, if game does not overwhelm a quad core then 7700k is slightly faster than a 8700k.
Next gen Intel high end 10 cores only make this situation worse.
The problem for Intel right now is more core == less gaming performance.
This is their fault in architecture, AMD does not affected by this. Each CCX is a 7700k equivalence and can enjoy low latency. For old games 1CCX is enough so Ryzen will act like a 7700k. For newer games they can group threads into group of 4 and make them run on different CCX to minimize cross CCX latency. And AMD is trying to improve that by adding a larger cache to the CCX.