Why defrag Windows XP Desktops?

People argue about whether you need to bother with defragging Linux and Mac OS X drives. A very few people even bother to argue about defragmentation of Windows machines. It's just a given - the machine is slow, defrag it. Case closed.

I've always been a little skeptical about defragging Windows desktops. Servers running databases or big apps, sure: defrag that puppy. But deskstops? What's going to get fragmented on a typical user's XP or Vista desktop machine?

In user file space, there are really only two areas that the ordinary user is likely to have fragmentation. One is Outlook PST files and the other is virus definition files.

Oh, sure, there are other places that get fragmented. The indexes for Temporary Internet Files, for example. Do you care? That's probably the first thing you clean up when your browser gets slow anyway, right? You might have some other large files of your own: big photos, a .zip file you downloaded.. are they slowing your system down? Of course not: maybe when you look at that photo it loads a little slower than it could, but so what? The zip file doesn't matter either - how often will you be unpacking it?

Windows Restore Point files are bound to be fragmented, but do you care? You aren't likely to access them at all, but if you do, an extra second or two because of excess file seeks is the least of your concerns.

With Outlook, you'd be far smarter to avoid large PST files anyway (and even smarter to avoid Outlook outright!). Either use IMAP or if you must put things in personal files, keep your Inbox and Deleted folders small. Make appropriate folders for things you want to keep and keep those folders lean and mean also. If you are so disorganized that you can't do that, at least move everything from Inbox once a month or once a quarter and just name the new folder "Inbox200812" or whatever makes sense to you. If you do just this (and don't use Deleted Items as a filing cabinet!) you'll likely eliminate any fragmentation that could happen here.

You can't control virus definition files, of course. They are going to get updated, and they are going to fragment. Unfortunately, as new definitions get downloaded very frequently, it's likely that they will re-fragment very quickly after you clean them up. You aren't going to spend hours defragging your disk every time a new file comes down, right?

Another place with a similar problem is Windows Update. The patch files aren't quite as frequent as virus updates, but again they are likely to get fragmented quickly. What can you do?

There is a single file defragger: Contig by By Mark Russinovich. This is a free download that you can use to target specific files rather than tying up your machine for hours running the disk defragmentation program.

Paging and Registry file fragmentation

Your Page and registry files can get fragmented. Unfortunately, these are off-limits to most defragmentation software. Mark Russinovich comes to the rescue again with PageDefrag, which runs as your system boots to reorder these files. But is there any point? I'm not convinced there is for your Page file(s). Your access to memory is very random, so what good can be accomplished by re-ordering things in swap? I just can't see that doing much of anything for you. As to the registry, I suppose if you are constantly adding and removing programs and you have a lot of them, your registry files might get big enough to benefit, but I bet it's rare to see more than one or two extents in any of them. No harm in running this once out of curiosity, but I can't see it as anything you'd use often.

I just took a look at my wife's XP box. It's several years old and if it has ever been defragged, it was a long time ago. Here's what the analysis phase said it found:

 Volume ACER (C:)
     Volume size                                = 25.25 GB
     Cluster size                               = 16 KB
     Used space                                 = 20.49 GB
     Free space                                 = 4.76 GB
     Percent free space                         = 18 %
 
 Volume fragmentation
     Total fragmentation                        = 16 %
     File fragmentation                         = 30 %
     Free space fragmentation                   = 3 %
 
 File fragmentation
     Total files                                = 63,417
     Average file size                          = 306 KB
     Total fragmented files                     = 3,712
     Total excess fragments                     = 17,943
     Average fragments per file                 = 1.28
 
 Pagefile fragmentation
     Pagefile size                              = 756 MB
     Total fragments                            = 9
 
 Folder fragmentation
     Total folders                              = 6,876
     Fragmented folders                         = 33
     Excess folder fragments                    = 118
 
 --------------------------------------------------------------------------------
 Fragments       File Size       Most fragmented files
 86              5 MB            \PHOTOS\2006\Roll 3\MOV00362.MPG
 249             114 MB          \WINDOWS\Installer\508A391.MSP
 215             7 MB            \WINDOWS\Installer\1A67BF3D.MSP
 153             6 MB            \WINDOWS\$HF_MIG$\KB956390-IE7\SP2QFE\IEFRAME.DLL
 145             11 MB           \Documents and Settings\All Users\Application Data\Symantec\LiveUpdate\Downloads\1195148577jtun_nav2k6enn01m25.m25.full.zip
 274             5 MB            \Documents and Settings\LINDA\Local Settings\Temp\ATT1.eml-2.txt
 193             384 MB          \Documents and Settings\LINDA\Local Settings\Temp\pft1A.tmp\QBooks\DATA1.CAB
 122             10 MB           \Documents and Settings\LINDA\Desktop\All Pictures\Thumbs.db
 102             2 MB            \Documents and Settings\LINDA\Desktop\All Pictures\P1010829.JPG
 102             4 MB            \Program Files\Common Files\Symantec Shared\VirusDefs\20080712.002\TCSCAN7.DAT
 267             8 MB            \Program Files\Common Files\Symantec Shared\VirusDefs\20080712.002\VIRSCAN5.DAT
 315             25 MB           \System Volume Information\_restore{3B5EBD63-0BA3-4CB6-8D46-0666EE4E44F9}\RP351\SNAPSHOT\_REGISTRY_MACHINE_SOFTWARE
 110             26 MB           \System Volume Information\_restore{3B5EBD63-0BA3-4CB6-8D46-0666EE4E44F9}\RP354\SNAPSHOT\_REGISTRY_MACHINE_SOFTWARE
 185             26 MB           \System Volume Information\_restore{3B5EBD63-0BA3-4CB6-8D46-0666EE4E44F9}\RP356\SNAPSHOT\_REGISTRY_MACHINE_SOFTWARE
 

Pretty much what I'd expect, right? She doesn't use Outlook, so none of that junk appears. The only other thing in the list that would ever affect day to day operation are the Symantec A/V files. We know that those are going to re-fragment quickly.. is there really any reason to defrag this disk?

Now of course there will be exceptions. Maybe you run a large database on your desktop. Maybe you regularly download large files for other reasons and use them regularly. You could have specific needs for defragmentation. But if you do, you probably know that already, right? For most people, housekeeping (cleaning up temporary files, keep PST files small) is likely to have more effect than defragmentation.