For a while i have wanted to play around with unlocking the full speed of my eeepc 701′s CPU, but have never found the time. Tthe other day i decided to change the standard Xandros eeepc operating system, toÂ something with a bit more flexabilty. I settled on eeeubuntu, and figured whilst it was a fresh install without anything i cared about on the system i may as well have a crack at overclocking it.
The process was fairly system and i documented the process should anyone else want to give it a crack. Be prewarned though these directions were what was involved in getting it working on the eeeubuntu distro, your mileage may vary depending on what your distro of choice is.
First up you need to create aÂ directory to download and build the kernel module:
tar zxvf eeepc-linux-0.2.tar.gz
(Depending on what distro you are using you may have to install any missing build tools such as make to your system, before you can finish the above step, eeeUbuntu had them already to go)
sudo pico /etc/modprobe.d/blacklist
Comment out line 25 which reads “blacklist i2c_i801″ by placing a # character at the start of the line.
sudo insmod eee.ko
After doing this you should now be able to see a new directory in the /proc folder called eee, which contains some new files which provide insight into the current state of your fsb, fan, cpu. The contents of these files can be easily examined with the cat command e.g cat fan_rpm will display the current fan speed. The contents of these files are as follows:
fan_manual – Controls if the fan speed is controlled automatically (0) or is manually controlled by the user (1)
fan_rpm – The current speed of the fan in revolutions per minute.
fan_speed – The fan speed setting in percent 0 being not moving, and 100% being flat out. Note that if the fan speed is automatically being set by the BIOS this will read 0, although the fan is going.
fsb – The front side bus settings – bus speed / MDivisor / CPU voltage mode.
pll - phase locked loop, it is used to generate the fsb on the eeepc
temperature – The current CPU temperature in degrees celcius.
To ensure the module created is still loaded when you next restart the machine copy it to:
sudo cp ~/tmp/eeepc-linux/module/eee.ko /lib/modules/(kernel name)/kernel/drivers/acpi/
To find out the name of your current kernel type the command uname -r at the command prompt and modify the path you are copying to, in my case its /lib/modules/2.6.24-16-generic/kernel/drivers/acpi/.
Now you have to register the module with the command:
sudo depmod -a
Then edit the modules file with:
sudo pico /etc/modules
And add the line “eee” to the bottom of it, when you next reboot the machine the module should be available from the get go.
Now down to the nitty gritty of changing the FSB speed
sudo sh -c ‘echo 85 24 1 > /proc/eee/fsb’
Changes the FSB speed to 85 mhz, changing straight to 100 mhz is likely to end with the system locking up so it is better to increase the bus speed in increments.
sudo sh -c ‘echo 100 24 1 > /proc/eee/fsb’
Then changes the bus speed to 100 mhz, easiest way to get some sort of basic benchmark on the change is run the command glxgears for about 30 seconds after every increment and note the frame per second increase.
For further reading on the process i suggest you check out: