[Aengeuad]

  # echo performance | tee /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
  performance
  # echo ondemand | tee /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
  ondemand
  tee: /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor: Invalid argument
  # cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
  performance

The Arch Wiki suggests that both powersave and performance have dynamic scaling, and running 'watch -p -n 0.25 grep \"cpu MHz\" /proc/cpuinfo' indicates that both of them do, with powersave mostly sitting at 1.2GHz with occasional increases on a handful of cores while powersave fluctuates from 2~ to 4.2GHz across all cores with minimal load.

The linked docs from Clear Linux say that power draw isn't entirely dependant upon cpu frequency when there's no load so there's no issue with keeping it on performance, and I'm not about to doubt Intel here, but I'd be surprised if powersave didn't save power if only by clamping down how many resources programs can use. Anecdotally I've noticed that the powersave governor doesn't really work too well when doing things like running virtual machines and will keep the frequency very low, as if the scaler is blind to the resources the VM is using, while having it on the performance governor will pin all my cores to a far more appropriate 4.2GHz.