I'm trying to understand the CPU frequency scaling governors. My unRAID server runs on an i5 3470. Base frequency is 3.2Ghz, minimum CPU frequency is 1.6Ghz, and Turbo Boost can go up to 3.4Ghz quad or 3.6Ghz single. While Power Save does what I expect running the CPU most of the time at 1.6Ghz the Performance governor still scales the CPU frequency. It doesn't appear to get as low as the Power Save governor though. I'm used to the Windows "High Performance" power plan that seems to disable Intel's Speed Step and run continuously at the base frequency unless it needs more and kicks in the Turbo Boost.

 

Is there any way to get the same kind of "High Performance" mode that Windows provides?

I've looked at the intel_pstate driver docs here: https://www.kernel.org/doc/html/v4.14/admin-guide/pm/intel_pstate.html

 

I tried modifying the min_perf_pct in the /sys/devices/system/cpu/intel_pstate folder but that doesn't seem to do anything.

 

If I understand the docs correctly here:

 

Quote

Also, in this configuration the range of P-states available to the processor’s internal P-state selection logic is always restricted to the upper boundary (that is, the maximum P-state that the driver is allowed to use).

 

This seems to indicate that the performance governor should run the CPU continuously at the maximum speed. Why isn't this happening in unRAID?