Download STweaks. Reboot your device into custom Recovery Mode by powering it off, then holding down the volume up, Home and power buttons. Choose ‘install zip from internal storage’ and use the volume buttons to navigate to the zip. Press the Home button to start installing.Once completed, reboot your device. In your app drawer you will find the STweaks app. Run it and grant root access. Clicking on the GPU tab enables you to adjust the stepping levels of the processor. To start, try increasing each step by around 100Mhz.