Thats a ridiculously biased way to drive an explanation. You cannot arbitrarily take two different systems with different memory speeds and calculate core clock speed scaling. the 8600k at 5.5 Ghz is running at 1933 Mhz (DDR4 3866 Mhz) while the tpu review runs at DDR4 3200. Why don't you use the tpu 8600k results at stock with 4.1 Ghz all core turbo and 4.8 Ghz OC.
4.1 Ghz CB R15 MT score - 1051.66
4.8 Ghz CB R15 MT score -- 1196.14
1196.14/1051.66 = 1.137
4800/4100 = 1.170
So for a 17% clock speed scaling you get a 13.7% perf gain. 13.7 / 17 * 100= 80. Just like what I said. 80% perf gain for 100% clock gain. btw cinebench has very good perf scaling with core clock and maxes out the cpu at 100% usage. Not every app scales as well as CB. Now who was talking nonsense ?
Because at stock, speeds don't stay uniform across all cores, all the time. You can get single core and quad core speeds faster than all core speed, depending on how the load shifts.
So to properly check clock speed scaling, without the confounding factor of turbo boost, you have to run at speeds where the clock speed doesn't change with active core count, so above the single core turbo speed.
Which is why Comparing 4.8 vs 5.5 is a better scaling comparison, than anything at stock speeds with shifting turbo speeds.
If scaling was really as bad as you say, then 5.5GHz on another system should easily show the negative effect, regardless of other incidental differences.
Here is a CPU that doesn't have Turbo Boost to mess up the results (8350K).
https://tpucdn.com/reviews/Intel/Core_i3_8350K/images/cinebench_multi.png
@4 GHz: 683.88 cb
@4.5 GHz: 764.32 cb
12.5% clockspeed vs 11.8% performance. Very close to one to one.
Nowhere near the nonsense 60% scaling you claim.