Raspbmc Overclocking Guide

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Raspbmc Overclocking Guide

This guide assume that you have Putty on your computer and that you know how to connect to Raspbmc via SSH. If you you do not, please refer to HTPCBuild.com Connecting to Raspbmc via SSH Guide.

You’ve decided that you want to overclock your Raspbmc distro. We’ll need to use Putty to connect to your Raspberry Pi and edit the “config.txt” file.

1. First connect to your Raspbmc Raspberry Pi via Putty SSH.

2. Now we need to locate the “config.txt” inside of your Raspbmc distro. The “config.txt” file is located inside the boot directory. To move into the boot directory execute the following command:

cd /boot
The terminal will now show it has enter the boot directory.
3. Now you are in the boot directory. You can quickly check to make sure the “config.txt” file is inside of this directory by executing the following command:
dir
The terminal will echo back the contents of the boot directory. Here we see that the boot directory contains a file “config.txt”.

4. Now we can open up the “config.txt” file. Here we will adjust different clock parameters or add parameters if needed. To open the “config.txt” file execut the following command:

sudo nano config.txt

5. A text editor will launch and display the contents of the file “config.txt”.

6. Here comes the fun part! Here we can enter parameters we wish to add to the “config.txt” or we can adjust parameters already in it. There are a few clock values that you can adjust for your Raspberry Pi:

  • arm_freq – Sets the frequency of ARM processor. The default value is 700. (MHz)
  • gpu_freq – Simultaneously sets the frequency for: core_freq, h264_freq, isp_freq, and v3d_freq. (MHz)
  • core_freq – Sets the frequency of GPU processor. This will have an impact on ARM performance. The default value is 250. (MHz)
  • h264_freq – Sets the frequency of hardware video block. The default value is 250. (MHz)
  • isp_freq –  Sets the frequency of image sensor pipeline block. The default value is 250.(MHz)
  • v3d_freq – Sets the frequency of 3D block. The default value is 250. (MHz)
  • sdram_freq – Sets the frequency of of SDRAM. The default value is 400. (MHz)

NOTE: gpu_freq controls three values simultaneously. If you wish to control these values independent of one another, you’ll need to disable gpu_freq and enable h264_freqisp_freq, and v3d_freq.

NOTE: There are two ways to deactivate a clock parameter, you can either completely delete the value from your config.txt or place a “#” in front of the parameter you wish to disable. Placing a “#” indicates that the corresponding line of code is a comment and will not be executed.

7. We can see that Raspbmc by default overclocks the arm_freq from 700MHz to 800MHz. Changing the value of arm_freq will set a new freq on the next boot. Here the value has been changed from 800 to 840, which well set the new frequency to 840MHz on the next boot.

8. To add a parameter that is not in the “config.txt” file simply enter it in a new line. Here the parameter gpu_freq as been added and set to 300. This bumps the stock value from 250 to 300.

NOTE: The parameter gpu_freq simultaneously sets the frequency for: core_freq, h264_freq, isp_freq, and v3d_freq.

9. When you’ve feel satisfied with your additions and changes, hit “Ctrl+O”. A small line will pop up near the bottom of the terminal asking you to name the file. Keep the same “config.txt” name and overwrite the current file.

10. To exit out of the text editor hit “Ctrl”+”X”.

11. Now reboot your Raspberry Pi, and the new settings will take effect! You can execute a reboot by typing the following command:

sudo reboot

NOTE: You can check your arm_freq by executing the following command:

cat /proc/cpuinfo

That’s it, you’ve overclocked your Raspbmc Raspberry Pi. Please make sure to take care when overclocking your Raspberry Pi. Make changes slowly and in small increments. By making subtle changes and testing your Pi you will be able to notice as the system becomes more and more unstable. Look for signs such as random an inability to boot, random freezing, random errors. If you encounter these, SSH into your Pi and back down on the settings. Another option when running into overclocking instability is overvolting. If you wish to experiment with overvolting an Raspbmc Raspberry Pi, please refer to HTPCBuild.com’s Raspbmc Overvolting Guide.