There are occasions when you need to run processor-intensive tasks on your laptop. These can lead to generation of heat to a level where the laptop automatically shuts down. To prevent this from happening and reduce the excessive generation of heat, you need to throttle the speed of the CPU. This helps to prevent overheating. To do this on Ubuntu, install the indicator-cpufreq applet.
sudo apt-get install indicator-cpufreq <enter>
Restart your computer, and you will find an icon on the task bar that lists a display similar to the one below, giving you options to throttle or control your CPU’s speed. Select the appropriate option based on your CPU’s current load and temperature.