So, you got yourself a brand new handy little Raspberry Pi, and you're thinking, “This thing sure is swell, but, it would be nice if it ran a little faster”. Well, never fear, because minimally overclocking a Raspberry Pi is easy as… pie!
The objective of this project is to perform a slight overclock of a Raspberry Pi Model B. The stock frequency of the Raspberry Pi's ARM processor is 700 MHZ. Following this tutorial, we will be overclocking the Raspberry Pi to 800 MHZ.
The Raspberry Pi wasn't made to be a high performance machine by any means. It's built as a compact system that can be used for all sorts of fun little projects. However, since we're the type of people who like to mess around with things and get the most out of them, it's fairly simple to overclock the Raspberry Pi. The nice thing about the Raspberry Pi is that not only is it relatively simple to overclock the ARM processor, but there are also numerous other ways the Pi can be overclocked. This project however will only focusing on overclocking the ARM processor.
While it is possible to overclock a Raspberry Pi during the initial configuration, if you don't do it initially, it can be done very easily. The first thing we'll want to do is check the current frequency of the processor. We can do this by using the following command:
$ dmesg | grep cpufreq
This command will return a few lines, the first of which should include the following.
cpufreq: min=700000 max=700000 cur=700000
This line shows us that the minimum frequency of the processor is 700 MHZ, the maxium frequency is 700 MHZ, and the current operating frequency is 700 MHZ. We're going to change that! To do so, we'll be editing the “/boot/config.txt” file. Open it in your favorite text editor, and take a glance at it. Down towards the bottom of the file, you should see the following line.
#arm_freq=800
If you have this line, simply removing the # will uncomment the line and set the frequency max to 800. If you don't have this line for some reason, add it (without the #). After doing this, you'll need to reboot the system to cause the changes to take effect. After the system reboots, open a terminal, and run the “dmesg | grep cpufreq” command again. If everything went as planned, the first line should now read as follows.
cpufreq: min=700000 max=800000 cur=700000
This shows us that while the CPU's minimum and current frequencies are still 700 MHZ, it's maximum frequency has been increased to 800 MHZ. By default, when overclocked, the Raspberry Pi dynamically adjusts it's CPU frequency when under load. We told it that the range of frequencies it can use is from 700 MHZ to 800 MHZ. Since it's not being taxed, however, it's still running at 700 MHZ. If you want to have the CPU always run at it's max frequency, you'll need to add another line to the config.txt.
WARNING
At one point, adding any lines to the config.txt that weren't currently in there were known to void the warranty of the Raspberry Pi. Proceed at your own risk
WARNING
If you're choosing to be a rebel, and risking voiding the warranty of your $40 Raspberry Pi, then, continue! To force the Pi to always run at it's maximum frequency, add the following line to the bottom of the config.txt
force_turbo=1
Save the file, reboot the Pi, and run the “dmesg | grep cpufreq” command again. If everything was done correctly, all three fields should now read 800000. If they do, congratulations, your Pi is now operating at the blazing speed of 800 MHZ. As fast as a Pentium III!!