If you're anything like me, you will root a phone as soon as practically possible. Aside from all the other benefits which I won't be going into here, it also allows you to control the CPU speed of your device, giving you the ability to get both better performance and improved battery life.

Benchmarks at stock speed

Benchmarks at higher clock speed

If you want to be a speed king, this guide will walk you through the basics of overclocking your device. I am assuming in this guide that you know the basics of using a custom recovery, so i'll not be going over that aspect too deeply.

Part one is the kernel. Simply put, the kernel is the lowest software element of your phone. It communicates directly with the hardware and enables your ROM to make use of your phone's hardware. If you search XDA, you will often find custom kernels for devices. A custom kernel is one which has been modified to communicate with your hardware in a different manner than it would be able to usually.

One of the main benefits of customising a kernel is that it allows you to tinker with the clock speed of your device. The phone I used for making this guide, the HTC Sensation, has a 1.2GHz processor, but depending on the kernel can go up to around 1.9GHz.

As I said, one good place to find custom kernels is XDA, simply check your device's subforum and see what options are available to you.

Generally speaking, if your device has a custom recovery, you will find kernels in an update zip. Simply copy it to your SD Card, boot into recovery and flash it in the same way you would flash a custom ROM.

If you have a kernel that needs to be flashed through different means, the site/thread you find it in should have the instructions of what you need to do. Follow them carefully.

Now that you have your custom kernel installed, you will also require a means to adjust your speed. Some ROMs, such as Cyanogenmod, include builtin tools to adjust your clock speed, otherwise you can find apps in the market which will allow you to do this. In this first part we will be using SetCPU, which is available both in the market and on XDA.

What you should see if things are set up properly.

When you open SetCPU for the first time, you will see one of two screens. One will have two options, "Autodetect Speeds Recommended" and "Show other frequency sets". If you see these options, your rom/kernel are properly setup for overclocking. Unless you have a specific reason to do otherwise, simply select "Autodetect Speeds Recommended".You might, however, see a list of processors. Generally speaking this happens if your ROM/kernel combo doesn't support/isn't properly setup for overclocking. If this happens, check the thread or site you found your kernel in, and you should find information on what to do.

This is where the magic happens

Once you have granted SetCPU superuser permissions, you will see the above screen. The main items on this screen are the two sliders, the top one for setting the maximum clock speed and the lower for setting the minimum speed.

For your maximum speed, set it in increments and use your phone for a while, doing things which will tax the processor. If you see no stability issues, feel free to increase the speed. Do this until you note system instability, and if you do, go down to the last speed where your phone was stable.

You can also set the minimum speed. When doing this it is very important that you don't set it too low, as this can prevent you from receiving calls/waking up your phone. Broadly speaking, setting your minimum to about half the stock speed is a good general area.

There is an option to set your speed at boot, but before you do this, if you press menu you will see an option that says "Safe mode instrutions" which will let you create a zip to flash from recovery, preventing the CPU settings from being applied at boot. This is very useful should they somehow go wrong and prevent booting properly. If you run into issues after setting the speed at boot, flash this zip in recovery and you'll be back in business.

The final option on the screen is a drop down list, which lets you choose governors. What a governor does is determine when to adjust speeds. Which ones you have access to depend on the kernel. The three most common options are as follows:

Ondemand: This will scale your clock speed based on how much you need. If you're simploy sending a text, for example, it will keep the speed near the minimum, while if you're running a CPU intense game, it will set it to the maximum.

Performance: This will keep your CPU at the maximum speed at all times. Useful if you're using a resource instense ROM on an older device, but this will drain your battery very quickly.

Smartass: Simply put, this will reduce your clock speed to your minimum when you turn the screen off, conserving battery power. This is where setting your minimum speed too low can be an issue, however. Otherwise it works similarly to the ondemand governor. 


Well, that's it for part one, and you should now have the basics for overclocking your device. If you run into issues, leave a comment below. Part two will run through some more advanced overclocking options and different apps for doing so.

This guide was written by Bruce Taylor - FYA News Writer