A disk defragmenter reorganizes fragmented files on a hard drive, helping laptops and desktop computers read files from the disk faster.
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After defragmenting, your computer will usually open programs and apps faster, so you spend less time waiting for them to start, and the drive doesn’t have to do the extra work that often ends up slowing it down.
In other words, if you want to improve your computer’s performance and it uses a mechanical hard drive, defragmenting it may be necessary, and on a regular basis.
In this article, you will learn what a disk defragmenter is, what it does, when and how to defragment your disk, and which programs can help.
What Is a Disk Defragmenter?
A disk defragmenter gathers and rearranges fragmented files on your hard drive, moving data blocks so that all the parts of each file sit next to each other. This reduces file system fragmentation, makes reading data more efficient and therefore improves the computer’s overall performance.
At the same time, it consolidates the free space into larger contiguous areas. It does not add any storage capacity, but new files are less likely to end up fragmented.
Operating systems usually include a built-in defragmentation tool, and you can also use third-party programs.
What Is a Disk Defragmenter For?
Every file on your computer, whether a video, a photo or anything else, is stored on the disk as small blocks of data, and those blocks don’t always end up next to each other.
The operating system knows where each block is, but as files are constantly written and deleted, it is not always possible to store all the blocks of a file in adjacent areas of the disk.
As a result, over time, the parts of each file become scattered across the disk, with gaps between them.
This is called fragmentation, and it is mainly a problem on mechanical hard drives.
Because the read/write heads have to move back and forth to collect file fragments scattered across the platters, the whole computer gradually becomes slower.
In other words, the system becomes less responsive and may take longer to complete some tasks.
So, the more you use the PC, saving and deleting files and installing and uninstalling programs, the more slowly it opens apps and programs, because the data is scattered across the hard drive.
The disk defragmenter reverses this process: it reorganizes the data on the hard drive and puts fragmented files back together, helping the computer work more efficiently. Note that this only applies to mechanical hard drives. SSDs must not be defragmented: they gain nothing from it and the extra writes wear them out (Windows detects SSDs and runs TRIM on them instead). Also, never defragment a drive you want to recover deleted files from, as moving data around can overwrite them.
When Should I Defragment My Disk?
Windows 10 and 11 optimize drives automatically once a week by default, so you usually don’t have to do anything. If you do it manually and you are a typical user (browsing the web, email, games and so on), defragmenting your hard drive once a month should be enough.
But if you use your PC 8 hours a day, for work for example, you should do it more often: about every 2 weeks.
As a general rule, whenever your disk is more than 10% fragmented, you should defragment it.
How Do I Defragment My Disk?
As we have seen, Windows already comes with a built-in disk defragmenter.
In Windows 7 and later, you can schedule defragmentation as often as you like.
To use the built-in tool, follow these steps:
- Open the tool: in Windows 10 and 11, type “Defragment and Optimize Drives” in the Start menu search box and open it. In Windows 7, go to Start → Control Panel → System and Security → Administrative Tools and click “Defragment your hard drive”.
- Select the drive and click “Analyze” (in Windows 7, “Analyze disk”). This checks whether the drive needs to be defragmented. A drive with 10% or more fragmentation should be defragmented (if you have been using the computer for a while without doing it, it may show 50% or more).
- When the analysis is finished, click “Optimize” (in Windows 7, “Defragment disk”). A progress indicator shows how the process is going. When it finishes, the tool will show that the drive no longer needs to be defragmented.
What Is the Best Disk Defragmenter?
As we have seen, besides the built-in tool, there are also third-party programs you can use to defragment your disk.
Let’s look at some alternatives and see which one is best:
Smart Defrag
Developed by IObit, this tool lets you exclude specific files and folders from defragmentation.
It can replace the Windows defragmenter, quickly optimize Windows (Metro) apps and skip files above a certain size.
Smart Defrag can also defragment at boot time to speed up startup, and it offers a game optimization feature designed to improve game performance.
The program also includes features to speed up access to frequently used files.
On the downside, Smart Defrag does not defragment while the PC is idle.
UltraDefrag
This Windows tool defragments both internal and external drives, can defragment individual folders and files and can also check the disk for errors, a useful feature that most defragmentation programs lack.
It offers a standard set of features anyone can use, plus many advanced options for users who want to fine-tune the program.
UltraDefrag also has a boot-time mode that can defragment system files, such as the registry, that are locked while Windows is running.
In addition, you can schedule automatic optimization with this tool.
The only drawback is that some advanced options require editing a configuration file, which can be tricky for non-technical users.
Auslogics Disk Defrag
In terms of features and value for money, this is the best disk defragmentation tool.
This Windows program optimizes your file system to make reading and writing files faster, and it shows you a list of the fragmented files rather than a vague fragmentation report.
It is free and also has a mode for SSDs that optimizes them without defragmenting, so you don’t need separate programs for hard drives and SSDs.
Besides defragmenting, Auslogics Disk Defrag can also clean up temporary and unnecessary files.
Its advantages are that it is lightweight, easy and practical to use, and available in a portable version.
Its drawbacks include not being able to defragment at specific times or when the system is idle.
Defraggler
Available only for Windows, Defraggler lets you defragment individual files or the entire disk at once.
Being able to defragment individual files helps keep the files you use most running fast.
After running an analysis, it lists all the fragmented files on the drive, and you can choose which ones to defragment.
Its features include scheduled automatic defragmentation, excluding specific areas from defragmentation and disk optimization.
Its advantages include defragmenting on a scheduled date or automatically, defragmenting during a reboot, and working well with external drives and USB flash drives.
On the other hand, the installer offers to install Google Chrome by default (you can uncheck it), and the program does not defragment while the PC is idle.
MyDefrag
A highly customizable free defragmentation program, MyDefrag offers three levels of disk optimization for better data placement.
Its advantages include a clean, organized interface and defragmentation of removable drives.
However, MyDefrag is complicated for non-technical users and has not been updated in a long time.
Does Defragmenting Your Disk Increase Your Internet Speed?
No. Defragmenting does not change the speed of your internet connection, which depends on your network and your provider.
What it can do, on a mechanical hard drive, is make the computer feel more responsive: with files better organized, the system finds data more quickly and responds faster to what you do, including opening the browser and saving downloaded files.
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Conclusion
A disk defragmenter improves the performance of computers with mechanical hard drives by reorganizing fragmented files.
As a result, the operating system finds data more quickly and responds faster to user commands.
You notice this in everyday tasks, such as starting the computer, opening programs and opening or saving files.
However, to be effective, defragmentation needs to be done periodically, at intervals that depend on how much you use your computer.
Finally, remember that Windows has a built-in disk defragmenter that can be used to improve your computer’s performance, but there are also third-party defragmenters with different features.
Whichever defragmenter you choose (built-in or third-party), remember to defragment your hard drive regularly, and never your SSD, to keep your computer performing at its best!
Also note that if defragmentation is extremely slow (more than 6 to 10 hours) or gets stuck, it may be a sign of bad sectors on the disk. In that case, stop the process and stop using the disk, as defragmenting a failing drive puts heavy strain on it. If it contains important data, take it to a professional data recovery company.
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