What is the best UE4 PC setup? (Mainly CPU) And why?

Clock speed is a good indicator of performance, especially between processors of the same architecture, but it is not always accurate - especially between different models or brands; Even more-so when one considers multiple cores, high spec server processors for example may have upward of 32 cores, yet often have lower clock speeds.
It’s a misnomer that higher clocks are always better, even though that is correct for the majority of cases.