When running intensive apps like blender my CPU can get up to 80.C I can manually underclock the CPU from the BIOS but I would like to have my pc detect when the CPU temp gets too high and slow things down until everything cools down. Is there a way to do this automatic or even a manual way to slow the CPU down from ubuntu

  • 2
    This looks like a feature request for Blender in the meantime. You can manually use Performance Governor and stop apps manually with the system monitor.
    – userDepth
    Jan 24, 2017 at 21:09

3 Answers 3


Intel Ubuntu 16.04+ solution for Sandy Bridge and newer processors

From (wiki.debian.org -thermald) there is Debian's (Ubuntu's) write up about thermald A Linux daemon for cooling tablets and laptops. This only works for Sandy Bridge (2nd generation) and newer Intel Cores. Once the system temperature reaches a certain threshold, the Linux daemon activates various cooling methods to try to cool the system.

Linux thermal daemon (thermald) monitors and controls temperature in laptops, tablets PC with the latest Intel sandy bridge and latest Intel CPU releases. Once the system temperature reaches a certain threshold, the Linux daemon activates various cooling methods to try to cool the system.

It operates in two modes:

Zero Configuration Mode

  • For most users, this should be enough to bring the CPU temperature of the system under control. This uses DTS temperature sensor and uses Intel P state driver, Power clamp driver, Running Average Power Limit control and cpufreq as cooling methods.

User defined configuration mode

  • This allows ACPI style configuration in a thermal XML configuration file. This can be used to fix the buggy ACPI configuration or fine tune by adding more sensors and cooling devices. This is a first step in implementing a close loop thermal control in user mode and can be enhanced based on community feedback and suggestions.

How to install

apt-get install thermald


From Arch Linux:

TLP brings you the benefits of advanced power management for Linux without the need to understand every technical detail. TLP comes with a default configuration already optimized for battery life, so you may just install and forget it. Nevertheless TLP is highly customizable to fulfill your specific requirements.

Please read the full Arch Linux TLP link above. There are issues with Nvidia that require configuration changes.

After many trials and errors with other packages, I've had great success using TLP. It gives superior fan control and works seamlessly with thermald and p-states.

As these installation instructions for Ubuntu 15.04+ mention TLP not only reduces overheating but it extends battery life too.

Since installing TLP, Powerclamp (described below) has never been invoked again.

Intel Powerclamp

Intel's Powerclamp driver is defined here (kernel.org - Intel Power Clamp.txt) and is part of thermald described above. A direct quote for Powerclamp from the link:

Consider the situation where a system’s power consumption must be reduced at runtime, due to power budget, thermal constraint, or noise level, and where active cooling is not preferred. Software managed passive power reduction must be performed to prevent the hardware actions that are designed for catastrophic scenarios.

Currently, P-states, T-states (clock modulation), and CPU offlining are used for CPU throttling.

On Intel CPUs, C-states provide effective power reduction, but so far they’re only used opportunistically, based on workload. With the development of intel_powerclamp driver, the method of synchronizing idle injection across all online CPU threads was introduced. The goal is to achieve forced and controllable C-state residency.

Test/Analysis has been made in the areas of power, performance, scalability, and user experience. In many cases, clear advantage is shown over taking the CPU offline or modulating the CPU clock.

How do you know Powerclamp is running?

Powerclamp might only show itself once a year when your fan vents get too much dust & lint. So how do you know it's actually running in the background? Use:

lsmod | grep intel

And you should see a list similar to this:

btintel                16384  1 btusb
bluetooth             520192  29 bnep,btbcm,btrtl,btusb,rfcomm,btintel
intel_rapl             20480  0
intel_powerclamp       16384  0
   (.... more intel drivers ....)
snd                    81920  18 snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_hda_codec_idt,snd_pcm,snd_seq,snd_rawmidi,snd_hda_codec_generic,snd_hda_codec,snd_hda_intel,snd_seq_device

If you see intel_rapl and intel_powerclamp you know it's working and simply waiting temps to exceed 85C.

Powerclamp in action displayed by Conky

Here is a screen shot when Powerclamp injects sleep cycles:

Kidie Injection

Normally on this system CPU clock speed is 2400 Mhz to 3400 Mhz when watching HTML5 video and 10 Chrome tabs open. Normally CPU utilization is about 9% to 12% across 8 CPUs. When things get too hot (86C) Powerclamp kicks in and this happens:

  • CPU speed is reduced to 1200 Mhz.
  • CPU utilization spikes up to 80%. This is misleading because the extra 70% is sleeping time.
  • The top 9 CPU processes are usually 5 or 6 Chrome processes plus Xorg, Conky, Pulse Audio and an occasional kworker. However now 8 of the top 10 are the kidle_inject/x process where x is from 0 to 7. For the first 8 CPUs.

The Powerclamp driver runs until temps drop below 85C again. While the driver is running you might have split second pausing in your videos and possibly split second keyboard and mouse lag.

Disable Intel Turbo Boost

Back in the "cool old days" of Ubuntu 14.04 Intel Turbo Boost was broken so my processor speed fluctuated between 1200 Mhz and 2400 Mhz. After upgrade to Ubuntu 16.04 it would go up to 3400 Mhz (3.4 Ghz) because Turbo Boost was finally working. But it also raised the heat.

To disable Intel Turbo Boost use:

echo "1" | sudo tee /sys/devices/system/cpu/intel_pstate/no_turbo

Short term fix in this scenario

To "band-aid" fix this problem I pulled the old laptop cooler pad with dual fans out of the closet and popped under the laptop. This dropped temps to 63C under the same workload.

The next step will be compress air in vents. After that the final step will be new Cooling Heatsink with pipes for CPU and GPU. Good thermal paste such as Arctic Silver 5 is also needed in that operation. A new fan was already installed last year and that seems to be running ok.

Update Jan 25 2017

Blew out fan vents with compressed air and temps dropped from 63C to 56C. This is still using the laptop cooling pad mind you.

Update Aug 06 2017

Have been using TLP (described above) for many months now and temperatures are steady around 50C and fan performance is optimal.

Watch out for too many fan control drivers

Because this is a Dell I had installed I8K Fan Monitor / Control in hopes it would speed up the fan sooner and faster. When I type sensors I get:

$ sensors
Adapter: Virtual device
Processor Fan: 3963 RPM
CPU:            +63.0°C  
Ambient:        +49.0°C  
GPU:            +54.0°C  
Other:          +79.0°C  

Adapter: Virtual device
temp1:        +27.8°C  (crit = +106.0°C)
temp2:        +29.8°C  (crit = +106.0°C)

Adapter: ISA adapter
Physical id 0:  +65.0°C  (high = +87.0°C, crit = +105.0°C)
Core 0:         +65.0°C  (high = +87.0°C, crit = +105.0°C)
Core 1:         +64.0°C  (high = +87.0°C, crit = +105.0°C)
Core 2:         +63.0°C  (high = +87.0°C, crit = +105.0°C)
Core 3:         +57.0°C  (high = +87.0°C, crit = +105.0°C)

Ignore the virtual temps, they are out to lunch. Under Ubuntu 14.04 the were accurate and I used temp 1 in Conky display. After Ubuntu 16.04 upgrade I had to refer to a third temperature not displayed on this screen. To see the REAL temps you can use this command:

$ cat /sys/class/thermal/thermal_zone*/temp

When I type:

$ lsmod |grep dell
dell_wmi               16384  0
sparse_keymap          16384  1 dell_wmi
dell_laptop            20480  0
dell_smbios            16384  2 dell_wmi,dell_laptop
dcdbas                 16384  1 dell_smbios
dell_smm_hwmon         16384  0
wmi                    16384  1 dell_wmi
video                  40960  3 dell_wmi,dell_laptop,i915

I see the dell_smm_hwmon kernel module / driver. When I google that driver and I8K people report the two drivers cause system freezes for a split-second every 10 seconds or so. I was having this problem myself so had to remove I8K fan control.

There are lots of other utilities and cooling methodologies but this is getting TL;DR.

  • 1
    Wow, thats quite the answer. Lot of cool stuff here.
    – Qwertie
    Jan 25, 2017 at 1:35
  • I have thermald installed, but how to run powerclamp? Is it running by default? what temp is it trying not to surpass?
    – user47206
    Jan 25, 2017 at 8:51
  • @cipricus When you use: $ lsmod | grep power you should see this: intel_powerclamp 16384 0. If not Powerclamp might be blacklisted for some reason. The threshold temp is 85C but I think you can change it. See: bugs.launchpad.net/ubuntu/+source/linux/+bug/1389077 Jan 25, 2017 at 11:23

I created a program just for this problem. Limit your CPU based on a desired temperature. It runs like this:

sudo ./temp_throttle.sh 80

That command will make your CPU cores slow down when they reach 80 degrees Celsius. When the temperature goes down, the CPU cores will be allowed to run faster again. You can find temp_throttle here.

To run the main script at startup with sudo and enter the password in gnome-terminal, one could create a small script :


cd "/path/to/the/directory/temp-throttle-stable/"
gnome-terminal -e 'sudo ./temp_throttle.sh 80' --geometry=45x15 --hide-menubar --profile=hold  

(--geometry=45x15 opens a small terminal screen; --profile=hold uses a gnome-terminal profile called "hold" that has to be already created with the option "When command exits: Hold the terminal open", --hide-menubar hides the menus for that window)

After making it executable, this small script (let's call it temp_throttle_80.sh) can then be added to the startup list and you'll be prompted to enter password at startup; then, if the mentioned temperature is reached, its action is reported:

enter image description here

  • 1
    Nice script. I also made a script to put pc to sleep when it reaches to a max temp. link
    – kenn
    Dec 25, 2013 at 20:18
  • 1
    It is a great answer and works in 16.04
    – user47206
    Jan 25, 2017 at 7:14
  • Scripts that need sudo powers I put into cron using the reboot options. That way no password needs to be entered on boot. There are other ways of doing it but cron was the easiest for me to setup. Jan 26, 2017 at 0:17
  • FYI the answer I posted on Intel Powerclamp throttles back CPU to lowest speed. However it also injects idle states to make CPU do nothing. I think your script is great but you might want to know what Intel is doing. I believe it is open source and you can study it if you are interested. Jan 26, 2017 at 0:28

you can limit the CPU frequency , so that you can low down the frequency and it can control the Heat from CPU.

cpufreq-selector -f <mention the frq u want in the Khz>
  • Is this permanent or will it go back after a restart?
    – Qwertie
    Dec 16, 2013 at 9:11
  • its a fixed set and if you want to modify it , again you have to.
    – rɑːdʒɑ
    Dec 16, 2013 at 9:13
  • You need to install gnome-applets for this to work
    – kiri
    Dec 16, 2013 at 9:26
  • @minerz029 this is a terminal command my friend.
    – rɑːdʒɑ
    Dec 16, 2013 at 12:18
  • 1
    @rajagenupula I get a command not found error The program 'cpufreq-selector' is currently not installed. You can install it by typing: sudo apt-get install gnome-applets
    – kiri
    Dec 16, 2013 at 20:19

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