Defraggler is a small utility for computers running Microsoft Windows that lets you defrag hard drives on your system. While Windows comes with a defragmenting utility, Defraggler has several unique features that Windows Defragmenter and third-party defragmenting software can't beat.
Defraggler is a quick, safe way to speed up your PC. Defraggler speeds up your computer by placing all the parts of a file on the same section of the hard drive. When Windows goes to access that file, it only has to look in one area of the drive, which speeds things up.
Defraggler also attempts to move all of your files to the start of the hard drive, which can make them faster to access.
While defragmentation is neither necessary, beneficial, or safe for solid-state drives, Defraggler also includes an optimization procedure intended specifically for solid-state drives to help keep their write speed more consistent. More information here.