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Kemzen
Asked: 2018-07-20 13:59:30 +0800 CST

change min and max cpu frequency

  • 772

Is there a way to change min/max frequency for the CPU in Ubuntu 18.04 Bionic beaver? I want to lower my max CPU frequency to maybe 1700000 to make my laptop run more silent. Below is CPU frequency results. 

$ paste <(cat /sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_min_freq) <(sudo cat /sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_cur_freq) <(cat /sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_max_freq) | column -s $'\t' -t
cat: '/sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_cur_freq'
800000 2194.934 2200000
800000 2194.911 2200000
800000 2194.916 2200000
800000 2194.940 2200000
cpu scaling frequency 18.04

3 Answers

  1. Best Answer

    Edit May 13, 2019 - simple bash GUI script

    I wrote this simple bash GUI script to change minimum and maximum frequencies:

    cpuf.png

    Original Answer

    Discover your Min/Max/Current Frequencies

    To discover your frequencies copy and paste this command into your terminal (without the $ or # prompts):

    $ sudo -i
# paste <(cat /sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_min_freq) <(cat /sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_cur_freq) <(cat /sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_max_freq) | column -s $'\t' -t
800000  900757  3500000
800000  921781  3500000
800000  857695  3500000
800000  904921  3500000
800000  816664  3500000
800000  845203  3500000
800000  892835  3500000
800000  844187  3500000
# exit
$

    The minimum frequency, current frequency and maximum frequency is listed for each CPU. In my case it is 8 CPUs, in your case it will be 4 CPUs (dual core x 2 threads per core).

    Values are listed in MHz with three decimals. So CPU 0 showing:

    800000  900757  3500000
    • Minimum Frequency 800.000 MHz
    • Current Frequency 900.757 MHz
    • Maximum Frequency 3500.000 Mhz

    How to reset Max Frequency

    To change the maximum frequency lower (you can't change it higher) use this command to change it from 2200 Mhz to 1700 Mhz:

    for x in /sys/devices/system/cpu/*/cpufreq/; do echo 1700000 | sudo tee $x/scaling_max_freq; done
    • 6

  2. I found the following project that worked for me:

    https://github.com/konkor/cpufreq

    It comes with a deb package for easy installation, for more info. read the installation README.md file

    https://github.com/konkor/cpufreq/blob/master/INSTALL.md#releases-page

    • 1

  3. Not in the kernel, but you can go into your BIOS/Setup and disable power saving features (which differ between main boards, so I don't know what those options are and therefore can't be specific). When you disable power saving features, you lock in the CPU to its maximum speed all the time.

    • 0