Five Best Disk Defragmenters

Your computer's a busy beaver, rapidly accessing and utilising files all in the name of bringing you what you want, when you want it. Sometimes it needs a little help tidying up, and that's where these five disk defragmenters come in.

Photo by Alex Witherspoon.

For those of you unfamiliar with the problem of file fragmentation, a quick—and quite simplified—primer is in order. Files are stored on a hard drive in blocks of data. The larger the file, the larger the number of blocks it is composed of. As your operating system accesses files, moves files around, and so on data blocks are not always arranged in the most effective manner. Imagine it like a messy office where as you opened file folders from your file cabinet you frequently placed documents from inside all over the room. You have a great memory, and you can find all the pages from each folder again if you need to, but you waste a lot of time just moving around looking for them.

In a perfect system the blocks of data that compose a file would be in the immediate vicinity of the file header, and your operating system would waste no time at all looking for the other pieces of the file. As it stands, however, on a badly fragmented disk the data can be scattered in pieces across the entire platter of the hard disk. The following defragmentation applications are specialised tools which will help you optimise your hard drive. Continuing with the analogy of the file cabinet, a defragmenter is the helpful assistant that comes in and alphabetises all your documents in the appropriate folders and file drawers for you.

If you're in the mood to dig into the more arcane aspects of the topic, definitely check out the Wikipedia entries on file system fragmentation and defragmentation. Now onto the top five nominees:

Auslogics Disk Defrag (Windows, Free)

Auslogics Disk Defrag is a simple disk defragmentation program. You can defragment multiple disks or select individual files or folders for defragmentation. Auslogics allows you to set the priority of the application and can tell your computer to shut itself down when the defragmentation process is complete—a handy feature when you want it to scan and defragment while you're sleeping but don't want to leave your computer idling all night. Auslogics Disk Defrag is a free and portable application.

MyDefrag (Formerly JKDefrag) (Windows, Free)

MyDefrag is an effective tool for defragmenting your disks. You can run it in default mode and get not only a defragmented disk but also optimised file placement; or you can tinker with it via scripting and further increase your disk optimisation for your specific needs. Even without its script support, MyDefrag does an excellent job defragmenting files and moving them to the optimum place on your hard disk. Files that are frequently accessed together are grouped together in zones for increased performance. MyDefrag will even scan the space allocated to the master file table and will move files from that space back to more appropriate places (sometimes when pressed for space Windows will dump files there, effectively orphaning them from the rest of the system).

Perfect Disk (Windows, $US29.99)

PerfectDisk is one of only two commercial entries in this week's Hive Five. One of PerfectDisk's biggest claims to fame is what they call "Space Restoration Technology". On top of optimising your disks during actual defragmention, PerfectDisk monitors disk writing to ensure that future files are written in the most efficient way possible in order to cut down on potential defragmentation. PerfectDisk will also analyse your data usage and create optimisation patterns suited for your style of file use and work. It can be scheduled or set to run when the computer is idle for continuous defragmentation.

Defraggler (Windows, Free)

Defraggler, from the same company that produces popular applications CCleaner and Recuva, is a portable defragmentation tool. It can scan multiple disks, individual disks, folders, or individual files for some quick, specific defragging. When Defraggler scans a disk, it shows you all the fragmented files and lets you either select sets to be defragmented or batch defragment all of them.

Diskeeper (Windows, $US29.99)

Like Perfect Disk, Diskeeper is packed with features not usually found in free defragmentation solutions. In addition to the basic defragmentation tools, Diskeeper can, for example, perform a quick defragmentation of system files on boot to keep your operating system running as efficiently as possible. Diskeeper, like Perfect Disk, has a system for continuously defragmenting files and optimizing new files for disk storage while you work. When you defragment multiple hard drives, Diskeeper selects different algorithms based on the disk—for example, it optimises your operating system disk differently from a media storage disk.

Have a strong opinion about defragmenting? Can't believe your favourite program wasn't included? Sound off in the comments.


    How about smart defrag?
    It's free, and it's pretty good.

      Smart Defrag is a really effective program in my experience, and free as well. That should be on the methinks. :]

    I find it so hard to compare defrag utilities when it's so hard to measure how 'good a job' each one has done - any ideas?

    How about a Mac?
    It's smart and doesn't need to defrag. Ever.

    ive heard macs dont need to be defraged why's that? or if thats a lie how do u do it?

    what about for da Mac??

    Do these work with SSDs?
    Do they make any performance difference on SSDs?

      From what I've read (at OCZ's website) you shouldn't defrag SSDs because it will reduce the life of the drive. For what reasons, I couldn't say.

      Regarding Macs and defragging, it's due to the file system used. The same applies for Linux/Unix OS. Yet another way for Billy Gates to make money out of you...

        Actually, there's simply no point in defragging a SSD.

        Defragging works by rearranging the physical location of the data on a harddisk so that the data fragments of a file are all located in the same area, thus speeding up access speeds.

        Optimisation basically utilises pixie magics to determine the arrangement of the files based on read/write frequency of the files, etc (varies from software to software I guess).

        Since SSDs do not work the same way as HDDs, there's no point in defragging SSDs.

    I will make the switch to Auslogics since its an Australian company, I have been using defraggler which has been fine.

    well, no matter the filesystem the physical way disks are accessed means defragging will improve it. i'm not sure on mac os but vista and windows 7 automatically defrag for you anyway. go and open disk defragmenter and it will say when it was last run.

    Saying a Mac doesn't ever need defragging is utter crap. While it may have a filesystem that manages files more efficiently, it can still be fragmented.
    I use iDefrag on a Mac. It's shareware, but fairly cheap and does OK.

    As people upgrade their version of windows this is no longer going to be an issue, since Windows Vista and Windows 7 both have defragment automatically.

    Please excuse my ignorance but why would one want to go to the effort to set one of these up when you can use the Windoze version? Are they that much better or is this just another way to show contempt for Micro$oft products?

    Every file system suffers from fragmentation.

    If Macs don't need to be defragged, why does Apple offer this?

    Also look up a tool called iDefrag. Also supports defrag on OSX.

    If you think OSX doesn't require defrag, think again. The OSX and linux file systems may be a bit smarter about fragmentation, but they still suffer from it.

    An effective method for defragging a Mac is to clone and copy back the hard drive using Carbon Copy Cloner or similar utilities.

    For SSD maintenance try the advice at Mac Performance Guide:

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