Comment 26 for bug 1885730

For example, the measurements on the X220 do not reflect situation on modern Intel systems, as they scale differently from Skylake and newer, as they do not have HWP.

A CPU with HWP (hardware P-states) behaves as you'd expect sort of - it runs at close to max frequency all the time, and scales down extremely in non-performance modes. It scales up and down faster than older models, given that HWP does the frequency scaling inside the CPU.

Disabling HWP gives you X220-style old scaling which is slower, and does not go as far down as the HWP scaling.