Yes. A hard drive. Not an SSD. NTFS.

As far as I know and see on the web - HDDs should be defragmented. That's why Windows NT does it in the background all the time. (Well, not really, since my computer is either in use or off.)

But apparently according to a user with high rep here:

There are tons of articles showing that defragging is no longer necessary.

I searched but couldn't find those articles. Not only that. I found many articles claiming the opposite. So, could someone please explain this? Perhaps, as with many other things, the answer is "it depends" - so what does it depend on?

Keep in mind that my question is not if there's a need for a 3rd party defragmenter, or if there's a need for scheduling a defrag, etc. My question is: On a Windows 10 system that is hardly ever idle, where all drives are the default NTFS, is there a need to use Windows' defragmenter?

  • microsoft placed 'Windows' defragmenter' in admin tools to be used, if in idle often or not. – mic84 Dec 9 '16 at 11:10
  • In my opinion, that depends on the usage of your computer, and size variety of files that reside on your drive. Let's say you delete a 1GB file, and NTFS is going to fill the gap with the next newcomer. But the new file is 1.5GB hence can't be put into gap, so inevitably causing fragmentation. Now, if you don't modify files often, and you moved all the temp and download folders to another volume, then you won't need fragmentation too often for windows volume! But, the other volume still needs fragmentation if you modify files too often. Less modify/delete/write=Less tendency to fragment – NetwOrchestration Dec 9 '16 at 12:59

As I often say, the guys who wrote the OS are pretty smart and know better. Usually (the initial releases of NTFS did not have a first party defragmenter, and they later found it was needed) . While this article is a decade old, NTFS is NTFS, and many of what it says is probably fundamentally still true. NTFS is designed to minimise defragmentation but eliminating it without some online, in process defragmentation process is hard.

Windows dosen't constantly defragment your hard disk. It periodically checks and does defragmentation if needed. And windows tries its best to keep files compacted as they're created - fragmentation happens when files are modified.

So, the scheduled, or even manual defragentation process is a preventive maintenance check. Its a little like checking your oil. You can pull out your dipstick and check, have some fancy thing that checks it for you (so cars have that?) and most of the time you should be fine. If it isn't, you'd have trouble and wished you checked.

As such, I'd leave the defaults as is. Manual defragmentation runs are probably no longer needed on 7 and better - since the system runs an automatic check every week by default, and defragments as needed.

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  • Thanks. However, something you said is unclear (to me). You said that Windows...periodically checks and does defragmentation if needed - did you mean even when the computer is being used, or are you referring to the auto-schedule? If the latter - your last sentence doesn't seem right (Manual defragmentation runs are probably no longer needed) in case of a Windows 10 system that is hardly ever idle. Or does it work while the computer is busy too? – ispiro Dec 9 '16 at 12:55
  • The auto schedule. But the 1st party defragmenter dosen't actually defragment if the drive is sufficiently defragmented. The process runs weekly by default. You hardly ever need to run a defragmentation run manually - as you did with XP since your system is doing it on the background anyway. – Journeyman Geek Dec 9 '16 at 12:59
  • Thanks. But it, then, seems that in my case I really should run it, because my computer is usually off at that time. Thanks again for your answer (and link!). – ispiro Dec 9 '16 at 13:02

The answer depends on the layout of the filesystem.

In the past we used FAT16 and later FAT32 which was later upgraded to ExFAT.

These filesystems store files in a linear order and when a file is removed, empty space is filled where previously was data. This causes for fragmentation and in these cases fragmenting a harddisk will help.

Because a harddisk that is fragmented becomes slower, developers wanted to find a way to get around the issue. NTFS fileystem was made which stores files differently. Due to how the files are stored, fragmentation is less likely to occur and for that reason you will likely not need to defragment the drive.

In addition, windows does defragment the drive on its own.

Windows 10 requires NTFS so the answer is: No, the user does not have to perform additional defragmentation.

That said, SSD's have their own defragmentation problems regardless of their filesystem.

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  • Thanks. I omitted explicitly mentioning NTFS. Fixed now. So basically, the answer is no. No need to defrag. And all those articles (found by searching the web) are simply wrong. Did I understand you correctly? – ispiro Dec 9 '16 at 11:17
  • @ispiro indeed, NTFS does not need to be defragmented. For that reason when you start the defragmentation tool it is ilkely that it will say that its not necessary. – LPChip Dec 9 '16 at 11:49
  • To whomever voted this answer down: please tell me why. – LPChip Dec 9 '16 at 11:49
  • All filesystems will face fragmentation. Otherwise, they would have to refuse storing files if no large enough contiguous space is available. I’m not aware of any filesystem doing this. Indeed, defragmentation is absolutely required. – Daniel B Dec 9 '16 at 12:13
  • @DanielB I agree, but given that windows does defrag on its own, the user does not need to also defrag. That's what I tried to answer. – LPChip Dec 9 '16 at 13:48

Defragmentation is not needed if you don't mind slow computer. Some filesystems needed to be deferagmented more often than others. Probability of fragments creation in partition which is nearly full is higher than in empty partition. This rule is filesystem independent.

I guess that defragmentation is sometimes needed to improve performance.

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