It is normally always preferable to use the intel-pstate driver compared
to pcc-cpufreq or acpi-cpufreq on modern Intel hardware.

Some HP ProLiant platforms implement the PCC interface [1] which can be
disabled by a BIOS setting in which case the PCC driver will not load
and the acpi-cpufreq driver can be used instead.

The intel-pstate driver is presumed to be better for Sandybridge CPUs
and later. Unlike the the cpufreq drivers, it uses P-states rather than
cpu frequency [2]. It also has access to CPU performance metrics so in
theory it has finer control than the traditional BIOS table driven
frequency scaling.

So for HP Proliants that are pre-Sandybridge, pcc-cpufreq may be the
best bet, providing the firmware is doing the right thing. If not, acpi-
cpufreq maybe better, as long as the BIOS has the correct control data
in the ACPI tables.

[1] Processor Clocking Control, 
https://acpica.org/sites/acpica/files/Processor-Clocking-Control-v1p0.pdf
[2] 
https://events.static.linuxfound.org/sites/events/files/slides/LinuxConEurope_2015.pdf

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https://bugs.launchpad.net/bugs/1806012

Title:
  set-cpufreq: 'powersave' governor configuration sanity on ubuntu
  server

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