Freeing Up Capacity On An SSD With NTFS Compression

Features
By Manuel Masiero, Achim Roos
published

Flash-based solid-state drives with more than 64 or 128 GB of capacity are fairly small, but they're still really expensive relative to hard drives. Compressing the Windows partition frees up some space, but is that really a good idea?

Should You Compress Data On Your SSD?

Activating NTFS compression is worthwhile on high-end computers with fast multi-core processors because you can squeeze more storage space from an SSD without compromising the system performance significantly. Our comparison to powerful compression tools like 7-Zip shows that NTFS compression isn't very aggressive and it excludes important Windows system files. Thus, it's not designed to extract every last bit of capacity that might otherwise be available.

But it's precisely this approach that ensures the processor is not too heavily loaded. Users with a modern dual- or quad-core CPU should not notice the additional load incurred by enabling compression. Due to the generally lower performance available from notebooks, the same wouldn’t necessarily hold true on mobile systems. Depending on the hardware, compression could both impact speed and take away battery life as a result of a higher processing load.

Backup tools should have no problems with compression, since the feature has already been integrated in NTFS for more than a decade, and is consequently well known to the developers of imaging software. We can't give you an overarching go-ahead, but we did run backups of our compressed system partition using Acronis True Image Home 2011 without any problems at all.

Despite moderate compression rates, NTFS compression does indeed conjure up some much needed free SSD space. On our test system, it gave us back an impressive 12.5 GB. This is a benefit to small SSDs, in particular. If you're only talking about a 60 or 100 GB drive, reclaiming more than 10 GB is huge. Owners of large SSDs should keep NTFS compression in mind too, though. So long as you have a fast-enough processor, there's no reason to not consider enabling it.

Ultimately, the amount of capacity you free up depends on the type of data you're compressing. Most media is already compressed, so there isn't much savings available there. However, compressible files like server logs and Excel data will yield a lot more space.

There's one more point to consider, though. With information being compressed on the fly, you're consuming more of an SSD's available write cycles than if you were writing the files uncompressed. This could have negative implications on the drive's endurance. Although we're not necessarily concerned about larger SSDs, models with less capacity inherently have lower endurance ratings. Thus, NTFS compression could conceivably affect their useful lives more significantly. 

Manuel Masiero
60 Comments Comment from the forums
  • compton
    I've been wondering about this very topic for a while now.


    However, in the conclusion, it is stated that compression ends up writing more vs. uncompressed NTFS, thus consuming more PE cycles. Shouldn't the opposite be true? When writing to the file system, if a file is compressible it should take up less space and therefore conserve more PEs (though actually compressing the files for the first time should result in more writes).

    Why does on-the-fly compression result in more writes even though the amount to be written is smaller?
    Reply
  • husker
    An interesting article, but seems a bit contradictory. Kind of like buying a Ferrari and then worrying about the gas mileage.
    Reply
  • because when you modify even just one byte of a file that is compressed, you can end up changing a significant portion of the file, not just that byte. it's good if you can fit the change in one block erase; what if you can't? you'll end up writing more info on the "disk" then.
    Reply
  • clonazepam
    I'd been wondering how I would fit the 20+gb necessary for sw:tor on the ssd (i said this previously, in the recent games on ssd vs hdd article). It'd be interesting to see the titles tested in that article with full drive ntfs compression on and off.
    Reply
  • Marcus52
    clonazepamI'd been wondering how I would fit the 20+gb necessary for sw:tor on the ssd (i said this previously, in the recent games on ssd vs hdd article). It'd be interesting to see the titles tested in that article with full drive ntfs compression on and off.
    Keep in mind, whatever storage option you use, you need room to install updates on top of installing the game, most especially for MMOGs. This means room to download the update AND install it.

    ;)
    Reply
  • Why windows are using ntfs instead of zfs or ext4 which are far superior than ntfs?
    Reply
  • BrightCandle
    Presumably this negatively impacts Sandforce based drives more than the Samsung by making the data stored compressed? Any chance you can do this with a Sandforce drive to see the impact?
    Reply
  • acku
    cruizerbecause when you modify even just one byte of a file that is compressed, you can end up changing a significant portion of the file, not just that byte. it's good if you can fit the change in one block erase; what if you can't? you'll end up writing more info on the "disk" then.
    Correctomundo. Compression involves replace repeated occurrences of data with references to a single copy of that data existing earlier in the input (uncompressed) data stream. That's why it's not right to think of a compressed archive as a container that stores any given file into a discrete space. If anything, the files kind of overlap in a big mixing pot.

    When you compress on the fly, you have to completely decompress all the files in an archive and recompress it when you're done. Hence it's all random transfers for the most part.

    BrightCandlePresumably this negatively impacts Sandforce based drives more than the Samsung by making the data stored compressed? Any chance you can do this with a Sandforce drive to see the impact?
    It's not a sequential transfer. Plus it's already precompressed data. Nothing SandForce can do about it. SandForce, Samsung, it's not going to make a difference.

    Cheers,
    Andrew Ku
    TomsHardware.com
    Reply
  • jemm
    SSDs manufactures do something in order to make it to the markeplace unexpensivelly! Economies of scale?

    Reply
  • chesteracorgi
    Do you have any data on how much using compression shortens the life cycle of the SSD? It would be most helpful as those with smaller SSDs are the likely candidates for using compression.
    Reply