...at the cost of speed. A big % of a computer's performance comes from its turbo clocks. For instance, the 16" MBP with 6 cores is 2.6GHz base, up to 4.5GHz turbo. Disabling turbo in this means you're slowing down the computer as much as 40%.
Also, it's questionable whether running at lower clocks saves power overall. Apparently it's more efficient to run higher clocks, but for shorter periods of time than it is to run medium clocks for extended periods of time.
I think there's a difference between turbo boosting for short workloads and turbo boosting for long workloads. Especially since a big cause of turbo boosting for long workloads is because of a bug in some app I'm running, like an infinite loop doing nothing useful.
Turbo Boost Switcher's website says it can adjust Turbo Boost based on fan speed (only in its Pro version). This is probably the best way to do it: disable Turbo Boost only when it's running for long enough to turn on the fan.
I honestly think a "no fan noise" setting should be a built-in feature.
This can extend your battery a decent amount, and obviously would cut down on fan noise.