A MacRumors thread post comes to the rescue of those that are stuck on iOS 4.3.x for whatever reason can enjoy a similar level of animation smoothness as once had on iOS 4.2.1. The following guide applies to both iPod touch and iPhone users.
To fix stuttering issues in 4.3:
- Before you start, it's recommended to backup your device via iTunes and start with a clean iOS 4.3.3 installation. Click "Restore" in iTunes to restore the original firmware to your device, then accept the backup prompt. Following the restoration process, select to restore from your most recent backup when prompted.
- Apply a jailbreak. You'll need this to access the system files on your device. You can use redsn0w. Follow the on-screen instructions.
- You'll need an application that allows you to access files on your device. For Windows, we suggest using iFunBox. Launch your file browser application, locate the entry for browsing the file system (in iFunBox, it's the Raw File System node), and navigate to /System/Library/CoreServices/SpringBoard.app/
- Locate a file labeled "NXXAP.plist". The iPhone 4 is "N90AP.plist," and the iPhone 3GS "N89AP.plist". The iPod touch 4G 8 GB has it as "N81AP.plist". Drag this file to your desktop and open it with your favourite text editor.
- Locate the two lines shown above. Change both lines to read as shown below:
- Save this file, then drag the file from your desktop back onto the file listing in iFunBox.
- Restart SpringBoard or restart your device (hold down the Power button, swipe the slider, then power the device back on).