Defragmentation explanation?


macrumors 6502
Original poster
Dec 2, 2009
As a new iMac user for the past four months, can someone please explain to me why it is suggested that Apple Computers do NOT need defragmentation, while PC's do? I have a 27" iMac, I love it, and have had absolutely no problems with it, and am not interested in purchasing defrag software, I just want to know how the Apple OS was designed so it wouldn't fragment, or so they claim. Thanks.


macrumors regular
Dec 18, 2008
Abbotsford, BC
I could be wrong, but I believe it's moreso because the OS defrags on it's own, really as it should be. There's a lot of scripts that run during the shut down/startup process, as well as even in the background during normal operation.


macrumors 6502a
Nov 7, 2009
In your basement
something to do with the OS doing it by itself in small chunks, I think.

that said, there was an article lurking around the net saying that there is a noticeable difference after defrag.

Then there's the anedoctal evidence.

So for my part, I'd take it all with a grain of salt, and the fact that most defrag software costs $100+ I don't bother.

If you really need contigious space, try the good old Carbon Copy, Wipe, Copy Back approach. Worked for me.


macrumors Core
Feb 9, 2008
It's not needed because of the way the file system works.

However if you take your computer to Apple "for check up and maintenance", what they go apart from the check up is defragmenting your drive.


Moderator emeritus
Oct 21, 2003
Portland, OR
Defrag is useful for people who work with very large files, e.g., large images and movies.. otherwise.. not so much. Any perceived gain would be miniscule. I haven't defrag'd a single mac under my care since Mac OS X came out and they're all doing fine. ;)