To reduce power consumption is essential for portable computers but there are no reason not to use on desktop machines. You can save power turning off not needed hardware components like WiFi, Bluetooth, turning off or reduce monitor backlight, spinning down HDD and to control CPU frequency.

TC4 activates CPU frequency scaling by default at startup time in case of suitable CPU found and enables 'ondemand' governor, which will select automatically frequency based on applications demand.

In most cases it works fine and you do not need any additional action.

If you want to view actual CPU frequency settings, install cpufreq-utils.tcz extension and use command:

cpufreq-info

Governors are kernel modules changing the CPU frequency. There are different governors implementing different rules:

powersave - sets the lowest possible frequency constantly
performance - sets the possible highest frequency constantly
ondemand - changes frequency automatically based upon actual demand of programs
conservative - same as ondemand but with a different algorithm, better for notebook battery use
userspace - allows userspace programs (or any process running as root) to set the frequency

Above governors are modules, loaded automatically when needed, but you can modprobe them before using. TC default is 'ondemand'.

For most systems, the 'ondemand' governor can provide the best compromise between heat emission, power consumption, performance, and manageability. When the system is only busy at specific times of the day, the 'ondemand' governor will automatically switch between maximum and minimum frequency depending on the load without any further intervention.

If you want to use a different governor the 'ondemand', install cpufreq-utils.tcz extension.

Use the 'cpufreq-set' command to activate one of the governors mentioned above, for example:

cpufreq-set -g performance

Please note, if you have a dual-core or multiple-core CPU, you must specify explicitely the CPU. There are CPU's where each core can run with different setting! Example for a dual-core CPU:

cpufreq-set -c 0 -g conservative cpufreq-set -c 1 -g conservative

You can explicitely specify the frequency also.

You can read man pages here:

http://linux.die.net/man/1/cpufreq-info http://linux.die.net/man/1/cpufreq-set

There are user space programs to manage not only cpu frequency but other components also. One of those, cpufreqd is available in the repository.