Question This is Interesting.

Just upgrades my Desktop to an ASUS RoG Striz Z390-E Gaming Motherboard with Intel i7 8700k Processor. The processor is rated at 3.7 Ghz. forgot what the Turbo was. I just checked it and it has consistently been running at 4.3 - 4.4 Ghz with no load to speak of. I have done nothing in the BiOS as far as OCing goes. It is a boxed CPU and not a binned one.
That's normal behaviour, the default all core TurboBoost for the 8700k is 4.3GHz, the CPU usually will not drop to the 3.7GHz base clock unless it gets thermal limited or power limited, which usually doesn't happen if you have good aftermarket cooling and a board with decent VRMs.

Realistically, these base clocks on Coffee Lake only apply if you want the CPU to strictly remain within the listed TDP spec, either due to poor cooling or poor power delivery on the motherboard. Otherwise, the CPUs will break past their stated TDPs to get higher clocks by default.