This works for me. Maybe it will work for you too.
I have these packages installed.
[root@thenudiebar ~]# rpm -qa|grep cpufreqcpufreq-1.0-28pclos2010
In the root terminal I type:
I get the frequencies available to me. The one to the left is the highest and the one to the right is the lowest.2800000
2100000 1600000 800000
Then I edit /etc/sysconfig/cpufreq file and add the minimum and maximum.
Looks like this:
# set cpufreq governor if defined
# possible choices are: ondemand powersave userspace performance
# minimum frequencyMIN_FREQ=800000
# maximum frequencyMAX_FREQ=2800000
# Uncomment to use acpi-cpufreq as fallback
Then I go into the PCC and set cpufreq to start at boot. Once I reboot I open a terminal and check the status with
[texstar@thenudiebar ~]$ cpufreq-info
cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to email@example.com
analyzing CPU 0:
CPUs which run at the same hardware frequency: 0
CPUs which need to have their frequency coordinated by software: 0
maximum transition latency: 8.0 us.
hardware limits: 800 MHz - 2.80 GHz
available frequency steps: 2.80 GHz, 2.10 GHz, 1.60 GHz, 800 MHz
available cpufreq governors: ondemand, conservative, powersave, userspace, performance
current policy: frequency should be within 800 MHz and 2.80 GHz. The governor "ondemand" may decide which speed to use
within this range.
current CPU frequency is 800 MHz
Install CpuFreqDisplay plasmoid from get more widgets and add it to your KDE taskbar to see it in action.