Scaling CPU frequency

Question

I've a Desktop and a Laptop with overheating issue and as far as I've known from Arch Wiki and other contributors on this site, I've to limit the cpu frequency to resolve the issue. On both system I've installed cpupower and sudo cpupower frequency-info on the Desktop with AMD Phenom(tm) II X4 955 Processor returns:

analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 4.0 us
  hardware limits: 800 MHz - 3.20 GHz
  available frequency steps:  3.20 GHz, 2.50 GHz, 2.10 GHz, 800 MHz
  available cpufreq governors: performance schedutil
  current policy: frequency should be within 800 MHz and 3.20 GHz.
                  The governor "schedutil" may decide which speed to use
                  within this range.
  current CPU frequency: 800 MHz (asserted by call to hardware)
  boost state support:
    Supported: no
    Active: no
    Boost States: 0
    Total States: 4
    Pstate-P0:  3200MHz
    Pstate-P1:  2500MHz
    Pstate-P2:  2100MHz
    Pstate-P3:  800MHz

and on the laptop with Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz returns:

analyzing CPU 0:
  driver: intel_pstate
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency:  Cannot determine or is not supported.
  hardware limits: 800 MHz - 3.50 GHz
  available cpufreq governors: performance powersave
  current policy: frequency should be within 800 MHz and 3.50 GHz.
                  The governor "powersave" may decide which speed to use
                  within this range.
  current CPU frequency: Unable to call hardware
  current CPU frequency: 1.70 GHz (asserted by call to kernel)
  boost state support:
    Supported: yes
    Active: yes

On the laptop, there's nothing with the word overclocking in BIOS BUT on the Desktop there's an Overclocking Profile and the contents inside that are:

Overclocking Profile 1  [None]
Overclocking Profile 2  [None]
Overclocking Profile 3  [None]
Overclocking Profile 4  [None]
Overclocking Profile 5  [None]
Overclocking Profile 6  [None]

OC Retry Count          [3]

lsmod | grep freq on the desktop returns:

pcc_cpufreq            16384  0
acpi_cpufreq           24576  0

and the same on the laptop returns:

pcc_cpufreq            16384  0

So, on laptop I, first, have to:

echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo

to disable boost and then on both laptop and desktop, I've to set the limit like this:

cpupower frequency-set -u 3.00 GHz
cpupower frequency-set -d 2.50 GHz

Do I have to enclose 3.00 GHz and 2.50 GHz with "" or '' or it'd be with underscore like 3.00_GHz and 2.50_GHz? Do I have to do anything on BIOS for the desktop? What are those available frequency steps on the desktop? Should I choose the values specified there for cap and floor for the desktop? Looks like there's no such frequency steps on the laptop so am I free to choose any value in between 800 MHz and 3.50 GHz for the laptop? What does current CPU frequency: Unable to call hardware mean for the laptop?

Answer 1

"CPU temperatures in linux: throttling or wrong reading?" is helpful with regard to frequency scaling and it actually solves the issue, I've tried with the maximum 2.5 GHz on both laptop and desktop and the laptop performs considerably better than the desktop with 2.5GHz.

Laptop never exceeded 80 degree while rendering a 16 min long video in kdenlive. On the other hand the desktop reached critical points: temp1 of PCI Adapter reached 85 and temp2 of ISA Adapter reached 93 several times while rendering.

---

EDIT

At 2.1 GHz Desktop is better than the Laptop! Core temperatures of the laptop were around 73C and never reached 75C whereas on the Desktop temp1 of PCI Adapter was around 56C, never reached 60 and the temp2 of ISA Adapter was around 65C, never reached 70C!

At this point, there's no difference between Windows 10 and Linux on these machines in terms of render time! The only difference on the laptop is Windows 10 would make some sound (like tapping on plastic) atleast once during rendering, I didn't hear that sound on Linux! However, I do hear the same sound on Linux If I disable intel_pstate!