The computer world is full of myths that have some element of truth.
However, many of these truths aren’t necessarily true anymore.
Technology advances at a rapid rate.
Advice that used to be true a few years ago may not apply anymore.
Defragging is one example of outdated advice.
Defragging has become less relevant as SSDs have gradually replaced hard drives in consumer PCs and laptops.
Does Defragging Speed Up Your Computer?
Defragging can improve your computer speed, but only if your Windows loads from a hard drive.
Even then, you’ll only see noticeable gains if your hard drive is nearly full or you haven’t defragged your drive in at least a few months.
Defragging is most effective when you have written and erased many files over a long time, resulting in many tiny file fragments.
Once you defrag your drive, it’ll be relatively fine for a while, but doing it every day won’t speed up your computer in any way.
To understand the rationale behind this answer, let’s explore how defragging works and why it might be helpful.
How Does Defragging Work?
To explain how defragging works, we need to explain how mechanical hard drives store data.
These drives consist of multiple spinning platters and a mechanical head that reads and writes data from and to these platters.
Suppose you want to write your first file to an empty hard drive.
The head starts from the first available sector and writes data in sequence until the file is completely written to the disk.
You can write multiple other files afterward, and they’ll all be stored in sequential order.
How Hard Drives Become Fragmented
Now, suppose you delete the first file and want to save a larger one.
The hard drive starts at the former position of the first file and writes byte after byte until it reaches the beginning of the second file.
Then it skips the non-empty sectors until it finds another empty sector to write the remainder of the new file.
The new file is now fragmented: divided into two or more parts when stored on the hard drive.
The disk head has to visit two places and travel a larger distance to read the new file.
As a result, reading the file takes longer than reading a file stored in a single location on the drive.
Now, imagine what happens after many files are written and deleted from your boot drive, something that Windows frequently does.
Your hard drive will have to work harder to read the files, making your system appear slower.
How Defragging Helps
As the name suggests, defragging reverses this fragmentation process.
It reassembles the file fragments next to each other on the physical platter so that the hard drive head can read them in one sweep.
It also rearranges all the free space on your disk into one big chunk so that new files can be written sequentially in the future.
That’s why your computer will seem faster after defragging a severely fragmented drive.
The process requires copying and deleting many file fragments.
It can take a few minutes to many hours, depending on your partition size, disk RPM, and the severity of the fragmentation.
Given how hard drives store data, your drive will become fragmented in the future, so you’ll have to defrag it regularly.
Why Fragmentation Isn’t A Serious Issue
Fragmentation used to cause performance problems back in the days of Windows 95.
However, new technologies slashed the negative effects and made them almost irrelevant.
You first need to learn about a certain computing concept to understand how this happened.
Windows needs a mechanism to organize and keep track of files stored on different drives and media, including hard drives, SSDs, thumb drives, and even floppy disks!
That mechanism is called a file system.
The File Allocation Table 16 bit (FAT16) was the first file system used in Windows 95.
FAT16 divided the hard drive into many clusters and assigned 16-bit addresses to each cluster.
Then it maintained a table to keep track of the data in each cluster.
It supported a maximum partition size of 2 GB.
Note: A cluster is a collection of sectors, the smallest unit of physical storage equal to 512 bytes.
When you write a file to your hard drive, it can’t occupy less than one cluster.
Therefore, even if the file is 1 byte, Windows won’t write any other data to that cluster.
Then came FAT32, which doubled the address length, allowing it to theoretically support up to 16 TB of storage.
In practice, the file system can handle a maximum file size of 4 GB and partitions smaller than 2 TB.
FAT16’s default cluster size was one sector for small partitions and increased to 64 KB when the partition was 2 GB.
Similarly, FAT32 started with one-sector clusters but only went up to 16 KB clusters for larger partitions.
The small cluster sizes made fragmentation a common issue with FAT drives.
They were also prone to file corruptions and weren’t fast enough.
Microsoft overhauled its file system with Windows XP.
They introduced the New Technology File System (NTFS), which overcame the limitations of the previous FAT-based designs.
NTFS uses 64-bit addresses for files.
It also has no practical limits on partition and file size, although the theoretical limit on file size is over 18 exabytes or 18 billion terabytes!
The default cluster size starts at 4 KB and goes up to 64 KB if your partition size exceeds 128 TB!
NTFS uses a few techniques to manage disk space much more efficiently than its predecessors.
Plus, it has a few advantages over FAT when it comes to fragmentation.
For one, because NTFS has larger clusters, files have some room to grow without being fragmented.
For example, if you start with a 1 KB document and gradually add more content, the file won’t get fragmented before reaching 4 KB.
NTFS handles large files more efficiently and has a read-ahead feature that increases the speed of reading fragmented files.
It also offers loads of features for extra efficiency, recoverability, and security.
For these reasons, running a defrag on an NTFS drive won’t lead to considerable performance gains.
How To Defrag Your Boot Drive
We only recommend defragging your boot drive (usually drive C).
You won’t see significant performance gains by defragging your non-boot drives since you won’t write as many files as Windows does.
Your operating system manages many tiny files.
These are often temporary files that only last a few minutes.
All versions of Windows come with a built-in utility to defrag and optimize your drives.
In addition, you can use third-party tools that give you extra options, such as excluding files from being defragmented.
These tools usually offer other optimization features, too.
How To Defrag Windows 11
Defragging on Windows 11 is quite straightforward:
- Search “defrag” in your Start Menu.
- Click on Defragment and Optimize Drive.
- Select the drive you want to defrag.
- Click Analyze.
- Once Windows checks your disk, select Defragment.
Warning: You can only defrag your boot drive if it’s a mechanical hard drive.
Windows 11 won’t let you defrag an SSD.
How To Defrag Windows 10
Defragmenting a drive on Windows 10 isn’t different from Windows 11.
As explained above, open the Defragment utility on Windows, analyze your disk, and defragment it if necessary.
Warning: Like its successor, Windows 10 only lets you defrag a mechanical hard drive.
How To Defrag Windows 7
Defragging on Windows 7 requires a couple of more steps:
- Open the Control Panel.
- Switch the View By menu to Large Icons.
- Navigate to Administrative Tools.
- Select Defragment and Optimize Drives.
- Choose the drive you want to defragment.
- Click Analyze.
- Once Windows is done analyzing your drive, click Defragment.
Warning: Although Windows 7 may allow defragging an SSD, you shouldn’t perform it (more on this later).
How To Automate Defragging
Defragging is inconvenient.
It takes time, and it’s hard to remember to do it.
Fortunately, you can schedule it to run every once in a while—we recommend monthly.
Follow these steps on Windows 10 or 11:
- Search “defrag” in your Start Menu.
- Select Defragment and Optimize Drives.
- Under Scheduled optimization, click Turn on (or Change Settings if you already have auto-defragging enabled).
- Select Run on a schedule and set the Frequency to Monthly.
- Select the checkbox that increases the task’s priority if it fails three times.
- Choose the drives you want to defrag. We recommend selecting only the boot drive to make the process faster.
- Select Automatically optimize new drives.
- Click OK and Close.
Note: The process is the same on Windows 7, but you’ll have to open the Defragment utility by navigating Control Panel > Administrative Tools > Defragment and Optimize Drives.
Defragging An SSD
So far, we’ve pointed out that you shouldn’t defrag an SSD, but we haven’t discussed why… until now.
Any modern PC will have an SSD as its boot drive to load the operating system.
SSDs are fundamentally different from hard drives in how they store data.
They have no moving parts—no head or rotating platters.
Instead, they store data on NAND chips on the drive’s board.
Each chip consists of numerous cells that store one to four bits, depending on the cell’s design.
They’re called single-level, multi-level, triple-level, and quad-level cells.
Penta-level cells are also emerging, capable of storing five bits of data simultaneously.
Because an SSD has no mechanical components, it takes roughly the same amount of time to access any cell.
Retrieving a fragmented file won’t take longer than a non-fragmented one.
Given this fundamentally different architecture, defragging has no positive effect on SSDs.
Moreover, it can damage your drive, although it won’t be severe.
Why is that?
SSDs can only handle a finite number of write cycles, usually indicated in terabytes written.
For example, a 600 TBW drive is guaranteed to work until you’ve written (and deleted) about 600 terabytes worth of data to it.
Once it passes that mark, the drive slowly loses its reliability, and the cells start to die.
It’s now clear why you shouldn’t defrag your SSD.
Doing so won’t immediately kill your drive, but it wastes its write capacity without providing performance benefits.
Does that mean you can’t do anything to improve your performance if you have an SSD?
How To Optimize An SSD
Instead of defragmenting, SSDs have a special TRIM command that can accelerate writing to drive and improve overall performance.
Unlike hard drives, SSDs can’t simply overwrite existing data.
Instead, the current data in a block must be replaced with zeros before the operating system can write new data.
The extra step in the process takes a bit of time and results in a perceptible delay.
However, using the TRIM command, you can fill the empty cell with zeros ahead of time.
This way, once the OS wants to write new data, it won’t have to spend time zeroing out all the cells.
Windows usually TRIMs your SSD automatically, but you can also do it manually.
The steps are identical to defragging a hard drive.
Here are the instructions for Windows 10 and 11.
- Type in “optimize” in your Start Menu.
- Select Defragment and Optimize Drives.
- Select your SSD. If you don’t know which drive is an SSD, look under the Media Type column.
- Click Optimize.
The process is fairly quick.
It’ll take a few seconds to a minute.
How Often Should You Defrag Your Hard Drive?
Modern versions of Windows usually perform the defragmentation process automatically at regular intervals.
You can schedule the task yourself if it isn’t already.
Given the advanced features of NTFS, you won’t need to defrag your boot drive more than once a month.
Moreover, you probably won’t need to defrag your other disks if you have your boot drive on an SSD.
To make sure, open the defragmentation utility in Windows by searching for it via the Start Menu.
Then check on the Current Status column.
If the disk is more than 10 percent fragmented, run the process.
It’s best to defrag your drives overnight when you don’t need to use your computer for other purposes.
This way, you won’t feel annoyed by the slow down you’ll experience while the process runs.
Frequently Asked Questions
1. Does Defragging Delete Files?
Defragging a hard drive only reassembles the files that have been divided into multiple sections and stored in different physical locations on the drive.
Therefore, you don’t risk losing your data when you defragment your drives.
That said, it’s always safer to regularly back up your data to avoid disasters in case of accidents or hardware failure.
2. How Long Does Defragging Take?
The duration of a defragmentation process depends on your drive’s size and how much data you have on it.
Larger drives with more files will likely take longer because moving the fragments around and consolidating the free space will require more time.
Moreover, if you haven’t fragmented your hard drive in a while, you can expect it to take longer since there will be more fragments to sort.
3. Does Defragging An SSD Damage It?
Defragging an SSD won’t kill it right away, but it wastes part of the drive’s finite write capacity.
Furthermore, you won’t see any performance benefits from defragging an SSD as these drives are fundamentally different from hard drives.
They can retrieve stored data rapidly regardless of where it’s stored on the drive.
To prevent wasting SSD write capacity, modern versions of Windows, starting with Windows 7, won’t allow users to defragment their SSDs.
Instead, they offer an Optimize feature that erases residual data on empty cells to make writing new information faster.
4. Does Defragging Help Gaming?
Defragging can improve your gaming performance by organizing your game files into blocks that your hard drive can read sequentially.
That way, the files will load faster, and you’ll probably experience less delay.
The effect can be more noticeable if your game is installed on your boot drive.
However, disk fragmentation is one of the least likely culprits if you’re experiencing low FPS and jitter during a game.
Investigate other causes and defrag your hard drive as a maintenance task.