Starting with Windows Vista, the built-in Windows Disk Defragmenter has been much improved upon, and more so in Windows 8 and Windows 7, and is considered to be much better than its predecessor Windows XP. The defrag engine and the manageability of fragmentation have been improved. The Disk Defragmenter runs as a low priority task in the background without affecting the performance of the computer. It runs only when the machine is idle! It uses the Task Scheduler to automatically keep the hard disk defragmented. This automated defragmentation does not affect the performance of the Windows.
