I decided that to properly test it I would have to run stress tests and properly measure the temps.
Note: Although you can stress test a newly overclocked system under Linux, it is strongly recommended that you don't do it. Why? You can experience data loss from the HDD depending on how your system fails in the event of an unstable overclock. Linux is less forgiving that Windows for rebooting from a hardlocked system without damage to the file system. If you insist on testing various overclocked levels under Linux, it is advisable to backup ALL important data first. Better yet is to install Arch to an old HDD and unplug your HDD(s) that carry your important data to iron out the overclock settings and arrive at a stable system.
To measure the temps I installed HddTemp and Lm-Sensors. I will give instructions for doing this in Arch Linux but I'm sure these packages are available for ubuntu and other Linux Distros in their respective repos.
To install hddTemp and Lm_sensors:
bash$ sudo pacman -S lm_sensors hddtemp
(HddTemp is not really necessary but its always a good idea to keep an eye on your hard drive temperature.) Read HERE for information on use.
You then need to set up Lm_Sensors:
bash$ sudo sensors-detect
And answer yes to all the questions.
Next you need to start the service:
bash$sudo /etc/rc.d/sensors start
I recommend that you automatically load the kernel modules at boot time by adding sensors to the DAEMONS array in /etc/rc.conf
(I Believe this is done automatically in ubuntu. )
eg: DAEMONS=(syslog-ng crond ... sensors ...)
You can then simply type:
to show your system temperatures.
Ignore the ALARM's etc as the program needs refining for some chipsets.
Now to set up a stress testing program. Prime 95 is known to be the best for windows and there is a version created for linux.
Firstly open your editor and paste the following into it:
echo "Downloading MPrime . Please wait. This may take some time........" ;
wget ftp://mersenne.org/gimps/mprime2511.tar.gz ;
echo "Installing mprime ............." ;
rm -rf mprime2511.tar.gz ;
sudo cp mprime /usr/bin/ ;
sudo chmod 755 /usr/bin/mprime ;
echo "mprime installed" ;
echo "Please read the README file" ;
Save the file as "installmprime.sh" with out quotes in your home folder.
chmod +x installmprime.sh
You will be prompted to enter your 'sudo' password. This is generally the same as your login password. If you don't use sudo please run this script when logged in as root.
You may now begin stress testing by typing:
and choosing menu option 15.
Click HERE for more information on using mprime.
To remove mprime simply type:
sudo rm -rf /usr/bin/mprime