Your computer is only as fast as its slowest link. The slowest link on a computer is its hard drive ^[1]. When Windows saves files it can get sloppy and split files up into pieces across the hard drive fragmenting them. When Windows accesses those fragmented files your hard drive it has to work extra hard to pick up all the fragmented parts of the files across the entire disk which slows your computer down.

The disk defragmenter takes fragmented files and puts them back together so that the hard drive doesn’t have to work as hard to get them.

By default Windows Vista’s Disk Defragmenter automatically defragments your hard drive(s) on a schedule for you. A normal computer user should never have to deal with the disk defragmenter in Windows Vista. Power users might find the command line defragmenter and its switches useful though.

Note: I don’t suggest buying a third party disk defragmenter ^[2]. The reason is the disk defragmenter included with Windows Vista takes many things into consideration when defragmenting your hard drives like file shadowing, backups, and many more. It might takes longer to defragment your hard drive using the included version, but it helps your computers overall speed in the long run.

Modify Disk Defragmenters Schedule

1. Open the Disk Defragmenter by typing defrag in the search box in the Start Menu and click Disk Defragmenter in the search results.
2. If you don’t want Disk Defragmenter to run automatically (not advised) uncheck Run on a schedule.

   ^[3]

3. To modify the schedule click Modify schedule.
4. Change how often, what day, and at what time you want disk defragmenter to run at.

   ^[4]

You can also defragment your hard drive(s) at any time by clicking Defragment now.

Command Line Disk Defragmenter

The command line version of Disk Defragmenter uses the exact engine as the GUI (regular) version but you have finer control of the defragmenter.

To use the command line version of Disk Defragmenter type defrag c: in the command prompt (with c: being the drive you want to defragment).

Switches

The command line version of Disk Defragmenter becomes much more powerful and flexible when you add switches to the defrag command. Below are switches that can be used when running the defrag command.

-c Defragments all drives.

-a Analyses the drives and gives you a report. It doesn’t defragment the drives.

-r Only defragments files that are smaller than 64MB in size. This is the default setting of the Disk Defragmenter. Microsoft research shows that there’s no performance gain when defragmenting files larger than 64MB in size.

-w Defragments all files regardless of size.

-f Forces Disk Defragmenter to defragment drives with less than 15% of hard drive space left.

-v Display a complete (verbose) report.

Examples:

defrag –c –w –f –v Defragments all hard drives and all files regardless of file size even if there is less than 15% of hard drive space left and gives a detailed report after.

defrag c: -w Defragments all files regardless of file size on the C: drive.