Years ago, I wrote a review comparing various disk defragmenters. To my surprise, the Disk Defragmenter in Windows performed as well as the retail defragmenters that were available at the time. (Further complicating matters, Disk Defragmenter was made by Executive Software, now called Diskeeper, which of course sells its own commercial disk defragmenter product.)

Effectiveness aside, there has always been one crucial feature missing from the Windows Disk Defragmenter: It could never be configured to automatically defragment your system's hard drives. Instead, you would have to run the application or manually or learn how to use the Task Scheduler to automate the process. In Windows Vista, that's all changed. And with Windows Vista Service Pack 1 (SP1) it's gotten even better.

The Vista version of Disk Defragmenter includes two huge improvements over its predecessors. First, the application sports a vastly simplified user interface that does away with the colorful but pointless disk layout view, which you could literally watch as your hard disk was graphically defragged.

Second, Disk Defragmenter can be automatically scheduled to run. Indeed, it runs automatically, by default, at 4:00 am every Sunday morning. This is huge, because disk defragging is one of those mundane chores that most users really don't have time to perform. But it's something that should happen regularly in order to keep your system performing optimally.

In the original shipping version of Windows Vista, that was all you got. The application appears as follows:

With Windows Vista Service Pack 1 (SP1), Disk Defragmenter has been updated significantly to address customer requests. Now, you can select which disk volumes are automatically defragged. (In the original version of Vista, all available disk volumes were automatically defragged.) As a result, the Disk Defragmenter UI has been updated to accommodate this additional choice. It appears as follows:

Windows Vista's Disk Defragmenter can be found at various points in the Windows Vista UI. In the Start Menu, it can be found in All Programs, Accessories, System Tools. The easiest way to launch Disk Defragmenter, as always, is with Start Menu Search: Tap the Start button and type defrag.

Fun fact: Disk Defragmenter rearranges fragmented files on your hard disk so that the PC performs better. Because disk fragmentation occurs over time, it worsens with the passage of time. Automatic disk defrag is an absolutely essential feature in a modern operating system.