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Defragmenting an SSD drive is a bad idea and Windows 7 is (should be?) smart enough not to schedule defragmentation on such drives.

However, I've opened up Disk Defragmenter on my system and found, to my surprise, that my SSD has indeed been defragmented... recently!

Then I checked the disks selected for the scheduled defrag (I have one SSD and one normal disk), and there the list correctly shows only the non-SSD drive.

This MSDN forum post seems to suggest that, at least on Windows 8, defragmenting an SSD drive will just cause the TRIM command to be sent to the drive, but there's no word on what actually happens if you try to defrag an SSD drive on Windows 7 (aside from the fact that it shouldn't happen automatically).

What happens in Windows 7 if one chooses to defrag and SSD? What could possibly have been the reason my SSD drive got been defragmented?

EDIT:

I just remembered - I've moved some folders (Users and ProgramData) from my SSD drive to my normal drive using junctions. This question suggests that this shouldn't have any effects at all on the defragmentation process, but could it have an effect on the "last run" in Disk Defragmenter?

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Seems like it does i.imgur.com/72OS1NM.png –  Oliver Salzburg May 29 '13 at 11:40
    
Only disks that can be defragmentet are shown... yet it will probably omit SSDs in the schedule configuration. I find this somewhat funny... –  Shaamaan May 29 '13 at 11:59

5 Answers 5

up vote 5 down vote accepted

By default, Windows 7 should automatically disable its scheduled defragmentation—but unfortunately, I’ve seen too many cases where the built-in Disk Defragmenter was still enabled, despite the fact that an SSD was built-in! Users should make sure that it’s disabled. Here’s how: Go to the Start menu and click on “All Programs”, “Accessories”, “System Tools” and “Disk Defragmenter”.

(Quoted from the Tune-up blog).

Microsoft confirm this here:

Windows 7 usually detects SSD disk after this has been installed or connected and integrates it properly. This also includes the detection that some services are disabled, which would restrict the functionality, performance and service life of the drive. First of all, you should check whether the automatic defragmentation is disabled. This is not the case, you should disable the automatic deactivation for the disc manually.

From these quotes I conclude that performing a defrag will actually do what it says (otherwise the warnings would be senseless).

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A WinSAT DiskScore >= 65 is required for Win7 to disable defrag on SSDs. –  Karan May 30 '13 at 16:02
    
@Karan By 65 do you mean 6.5, given that WinSat seems to give a score from 1 to 7.9? My SSD got a nice 7.9 on that. ;) –  Shaamaan Aug 26 '13 at 7:02
    
@Shaamaan: No, I meant 65 - it's the value stored in the registry. See the TechNet blog post referred to in the answer I linked to above. –  Karan Sep 6 at 0:34

I think though that it should defragment on demand if you tell it to. What if you want to add a new partition to the 'end' of the drive? You would need to defragment and consolidate the data to the beginning of the drive. Obviously the 'end' of the drive is a dubious phraase with SSDs, but as SSDs kind of emulate a mechanical drive and work within the mechanical paradigm for compatibility reasons, you may still need to consolidate the data.

Now there is a layer of wear leveling that most SSDs implement but most partition software only needs to detect that there is empty space at the end of the drive.

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just for your information if you want to defrag you might use the tool Contig its freeware from sysinternals (bought by Microsoft), after running it on an SSD today in verbose mode it showed it performed defragging on the disk. (which had trim support).

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When you use the software Magician deliverd with some SSD's, there you can choose whether you want performance or a long lifetime span. This refers also to the internal use of TRIM.

Windows itselfs has some same things when you change some settings in COMPUTER - PROPERTIES - PERFORMANCE.

In reality, with a MTBF of over 100 years sometimes, do not worry the first five years about defragmenting or not. You will only have some descendance in performance in write cycli, but not that desastrous as they "tell on internet about SSD's".

Your SSD will sooner get old fashioned than it will 'grow old' in using it...

Full performance tests with writing an SSD full is also not that good, but when you do sports and trainings and you aim for testing running above 30 km/h, it is not that good for your body neither. Which does not mean you would have to drop this competitive tests, I presume... We want to live indeed, I want my SSD to work also. And working and living includes usage damage. We really would NOT like it differently!

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Refer to Microsoft link below, to answer your question(s) on SSD (Solid State Drive) and Windows OS.. Pass the word on, to all that have brought one of these drives. http://support.microsoft.com/kb/2727880

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Can you summarize that link, so that if it goes dead or the website's link structure changes, your answer is still useful? –  John Bensin Oct 1 '13 at 13:23
    
This link is down which makes your answer useless. This is why you always should summarize your link as John said –  nixda Apr 24 at 8:12

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