Best Free Disk Defragmenters Tested

Ask a PC specialist or technician on how to make your slow, usually old computer to run faster again and they will advice you a common thing – defrag. Though defragmentation is not the only solution to the problem, fragmentation is a common problem to almost every slow computer.

That’s why we see dozens of defragmenters offering solution, some were free, some you need to pay to be able to use its full capabilities. For this article, we will examine some of the most popular free disk defragmenter to help you find which defragmenter is the best.

What is file fragmentation and defragmentation?

Let say you have a new computer. When you install and/or copy files to your hard drive, files and file fragments are copied and written next to each other. This is because there is plenty of free space. Then you begin uninstalling and/or deleting files. Your hard drive now looks like this. There are now free spaces between files.

And then you install new applications, or copy plenty of files, or edit a couple of videos. The new file will be copied on free space in-between, and if the free space is not enough, it will look for another free space to write the remaining part of the file, thus making the file fragmented.

If the file is fragmented when you access the file, the hard drive will look for another sector of your drive to find the remaining pieces of the particular file, making it slower to load and open.

Defragging/defragmenting is a process of putting together file fragments to speed up file access. That’s what disk defragmenter tools do. They also consolidate free space to avoid fragmentation of new files and put the most frequently accessed file on the fastest accessible part of the hard drive

Test System


  • Processor – Intel Celeron G550 2.6 GHz Dual-core
  • Memory – Geil 2GB DDR3-1600
  • Hard drive – Seagate 500GB hard disk, 55 GB System Drive
  • Video Card – nVidia GeForce 9600GT 512MB DDR3, Forceware 306.97

Operating System is Microsoft Windows 7 x64 with Service Pack 1. The 55 GB System Drive serves also as our test drive. All the applications and files used for testing are all in this drive.

Disk Defragmenters

  • Auslogics Disk Defrag 3.6.0
  • Defraggler 2.12.628
  • MyDefrag 4.3.1
  • O&O Defrag Free Edition 14.1.431
  • Puran Defrag 7.5
  • Smart Defrag 2.6
  • Ultra Defrag 5.1.1
  • Windows Disk Defragmenter


The following is the sequence we followed to do the tests for each disk defragmenter.

  1. Install all the necessary software, drivers, and all the disk defragmenter tools.
  2. Copy all the files that will be use for testing and running the benchmark.
  3. Create a disk image of the system drive.
  4. Do all the tests. This serves as our “Before” defragmenting results.
  5. Restore the image file of the system drive.
  6. Defrag using the Disk Defragmenter #N.
  7. Do all the tests. This serves as “Disk Defragmenter #N” results.
  8. Rerun step 5-8 using the next disk defragmenter.
  • We assigned points for each disk defragmenter to determine the best and worst performer for each test. We give 8 points for the best and deduct 1 point for each succeeding defragmenter. In case of tie, all the tied defragmenter will have the same point.
  • We included the “Before” defragmenting on the ranking, which means “Before” will also get points.
  • We rounded down the decimals of time in seconds. 5.6s and 5.1s are both 5s. In real time, you will not really feel the difference of 0.5s, 0.8s, even 0.1s so we decided to round down the decimals.
  • Aside from the defragmenting, we also used the optimization feature of the defragmenter, if available.
  • All time related tests were measured using a stopwatch.

Tests and Results

We used Defraggler to determine the disk status on “Before” and after defragging.

Fragmented Files Total Fragments Fragmentation % Free Space
Before 2781 (7.3GB) 26528 15 6.6 GB
Windows Disk Defragmenter 68 (1.6G) 646 2 7.3 GB
UltraDefrag 46 (2.7GB) 258 4 7.3 GB
Smart Defrag 2 56 (1.5GB) 1603 3 7.3 GB
Puran Defrag 59 (144 MB) 316 0 7.45 GB
O&O Defrag Free 41 (36.5 MB) 293 0 7.4 GB
MyDefrag 39 (33 MB) 131 0 7.4 GB
Defraggler 40 (32.5) 303 0 7.3 GB
Auslogics Disk Defrag 47 (37.8 MB) 189 0 7.3 GB

Each defragmenter reduced the fragmented files and size, the total fragments, and the percentage of fragmentation. But we found out that the number of fragmented files, the total fragments, and its percentage are not always relative to each other. Having lesser fragmented files doesn’t necessarily mean that you will also get to have lesser fragments and lesser percentage.

Take a look at UltraDefrag and Smart Defrag for example. UltraDefrag has lesser fragmented files and yet bigger fragmented file size. It also has lesser total fragments and yet higher percentage of file fragmentation. We also found out that you can also save additional free space after defragging. To be honest, I only found this out after doing the tests.

We didn’t include these results in our scoring because we are after the actual results and benefits.

Boot-up and Shut down

We used BootTimer to measure the boot-up time and a stopwatch for the shut down.


Defragging won’t guarantee faster boot-up. Here, O&O Defrag improve the boot-up time by 9 seconds, but Auslogics, MyDefrag, and UltraDefrag took longer boot-up time than before defragging. But every defragmenter took shorter time on shutdown compared to before defragging.

Disk Performance

Defraggler’s built-in benchmark tool guarantee us that defragging will improve disk’s random read speed, but CrytalDiskMark didn’t. Some defragmenter improved the random read speed, but worsen the sequential write.

PCMark Vantage

Defraggler gets ahead of the rest of the defragmenters followed by Auslogics Disk Defrag. MyDefrag, UltraDefrag, Smart Defrag gets lower points than before defragging, but the difference were small and it is almost negligible.


For gaming tests, we used Fraps to measure the frame per second for STALKER Clear Sky and the built-in benchmarking utility for Trackmania 2 Canyon.

Only Puran Defrag and O&O Defrag made improvements on launching the game after defragging, the rest were just as the same as before defragging. On the other hand, all of the defragmenters improved in loading level with Puran defrag made the biggest improvements of 8 seconds.

On frames per second performance, all of the defragmenters made no difference after defragging except for Puran Defrag, but even the 1fps improvement is insignificant.


All of the defragmenters made improvement in loading a level except for Smart Defrag while Defraggler, MyDefrag, and UltraDefrag made no difference in launching the game, the rest improved.

Auslogics Disk Defrag, O&O, and Smart Defrag made improvements on frames per second, the rest were just as the same as before defragging.

Opening PDF File

We used a 131 MB file as test file using Foxit Reader.

All of the defragmenters made no difference after defragging except for O&O Defrag and Smart Defrag which took 1 second longer

Opening Video File

We used a 775 MB, 1hr 35min .vob video file as test file, which was also the most defragmented file with almost 3,000 fragments before defragging. As we explained earlier, we expect the video to load and open faster after defragging.

Windows Media Player didn’t perform as our expectations as there were some which made no difference, others took longer to open, and only three made improvements. On the other hand, VLC gave us what we expect. All of the defragmenters made improvements and made the opening of video to be faster by 5 to 6 seconds.

3D Application – Blender

We used Blender as our 3D application and a small rendering scene as our test project.

All of the defragmenters sped up the opening of project by 2 to 3 seconds, but all of the defragmenters, except UltraDefrag, made no difference after defragging on rendering the scene. The 1 second improvement of UltraDefrag is almost insignificant.

Photoshop CS 5.1 x64

We used a 45MB psd project for testing the loading and opening speed, a custom action for the speed test, and save the file as PNG.

Almost there were no difference among the defragmenters in opening the project and saving in different format. In our speed test, only Defraggler made no improvement while the rest improved by 1 to 2 seconds.

Video Editing – PowerDirector 10

We used and 19MB, 220×176 wmv video file as our test file and produced it in WMV 9 HD Standard format, which is 1280×720 and with additional video effects.

All of the defragmenters made improvements on both launching the application and producing the video file, with O&O Defrag leading overall in this test.

File Archiving – 7-Zip

We used 70 jpeg files and a 976MB .exe file, for a total of 1GB as our test files for compressing and extracting using 7-Zip.


7-Zip didn’t show us that defragging will make extracting and compressing faster.


Winner – O&O Defrag Free Edition

O&O Defrag Free Edition tops our chart with 209 points followed by Auslogics Disk Defrag with 200 points and Defraggler with 198 points. The worst performer was Smart Defrag 2 which performed worse than before defragging.

Defragging, with the right software, will improve the overall performance of your computer. But for some specific tasks and specific software, like Photoshop and Blender, defragging won’t do anything to improve the performance. Only in Defraggler’s benchmarking utility and in video editing where all the defragmenters made improvement after defragging.

1 comment