I'm using a Thinkpad T14 gen1 AMD, with Ryzen 4750U processor. The power plan is set to "Balanced" already, but I noticed the CPU frequency is always near the max turbo frequency and the machine gets very noisy and hot when plugged in, even under light load.

Then I checked the advanced power settings and found the "minimum power state" is set to 80%, which is the default. I reduced it to 50% and the machine quiets and cools down, but the CPU frequency remains high. Now the machine is cooler in "Performance" mode than before in "Balanced" mode.

So I have these questions:
Is CPU frequency scaling no longer the primary way of reducing power? Do contemporary processors use C state and clock gating instead? (when not on battery?) So I should not look at CPU frequency in order to know CPU power state?
Does 80% minimum power state make sense? Why Windows choose such a default? Or is this value dictated by the laptop manufacturer (Lenovo)? I understand maintaining a high frequency improve system responsiveness, but it also accumulates heat, which limits the boost frequency and reduce system responsiveness under short burst load. On my machine, setting minimum power state to default 80% makes the "Best Performance" mode nearly unusable, because heat accumulation already situates the heat sink when the system is idle, so the processor triggers thermal protection soon after the load rises and let alone any frequency boost.