Download this app if: you want to change the CPU clock.
SetCPU is a tool for changing the CPU settings on a rooted Android phone or tablet. SetCPU works with a great variety of Android devices and ROMs, including the HTC One series, Samsung Galaxy series, and Nexus devices. You're under control: SetCPU can improve your performance, save battery, or...
Overclock or underclock — I love programs that allow me to take control over my phone and settings my carrier thinks I shouldn't play with. I actually prefer to underclock to save battery life. It doesnt really slow down any thing where I have my settings set at. The CPU rarely runs at full speed for a period of time,...