Disk fragmentation is generally main cause of slow and unstable computer performance. Smart Defrag 3 helps defragment your hard drive more efficiently and optimize your disk performance. Smart Defrag 3 is a FREE, light, and stable disk defragment tool that provides efficient defragmentation to hard drives for faster file loading and outstanding disk performance. It can work automatically in the background on your PC, keeping hard disk running at its top speed. Smart Defrag 3 now fully supports defragmentation on Windows 8/8.1 Metro Apps which accelerates the access to Metro Apps and allows for smooth performance on Windows 8/8.1.