Disk fragmentation can be a major contributor to slow and unstable PC performance. These tools quickly and effectively speed up your system by diagnosing and defragmenting your drives. Here are our picks for the best disk defragmenters.

Free disk defragmenter that is simple, clean, and easy to use. It doesn’t have all the advanced features that PerfectDisk has, but still does an excellent job defragmenting your drives and speeding up your computer. You can visually see what the program is doing as its running and it tells you the number of files that have been scanned and defragged.

PerfectDisk is a top notch disk defragmenter with several advanced features and a slick, easy-to-use interface. Standard defragmentation is fast and effective, and offline defragmentation lets you defrag system files that can’t be modified while Windows is running. You can also use the AutoPilot feature to automatically schedule disk defrag passes daily or weekly. While Auslogics is a better choice for most home users because it’s free, PerfectDisk is a better choice for advanced users and IT staff.

What’s the primary cause of slow/unstable PC performance? It’s disk fragmentation. Smart Defrag helps defragment your hard drives more efficiently than any other product on the market –– free or not. This powerful, award-winning free defragmenter is 100% safe and clean with no adware, spyware, or viruses.