How to enable speed step on core 2 duo

Before starting we have to discover which governors are avaiable for our processor:

$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors

The output should be something like this:

powersave ondemand conservative performance

Considering that in Ubuntu Gusty scaling is supported directly by the kernel we will to do nothing else than load the following modules:

cpufreq_conservative
cpufreq_ondemand
cpufreq_powersave
acpi-cpufreq

To do this we have to add the previous lines to the modules file:

$ sudo gedit /etc/modules

Now we can reboot the machine and enjoy the speed stepping. To set a specif governor we can type cpufreq-selector -g {governor}, here there is an example:

$ cpufreq-selector -g ondemand

We can also add the CPU frequency scaling monitor. To do this right click on the top panel and select Add to panel. Now we can drag & drop the gnome applet. To be able to change the governor from the applet we have to type the following command:

$ sudo chmod +s /usr/bin/cpufreq-selector