I am thinking of using NTFS compression (LZNT1) on my SSD using Windows 7, but I was a little unsure as to which folders would be a good candidate.

I was aware that Windows 10 has introduced new compression algorithms, and it can automatically compress operating system files using compact.exe /CompactOS

I thought it would be useful if anyone can shed light onto which files and folders are compressed automatically by compact.exe /CompactOS on Windows 10; both for Windows 10 users, and people who maybe want to try and implement their own compression.


Sadly I have yet to find a use for it

  1. It shouldn't be used on SSDs
  2. It shouldn't be used on system files
  3. It shouldn't be used on compressed files (which is almost all of them)
  4. You have to manually select which files to apply it to
  5. It is highly inefficient and sadly causes a much bigger slowdown when it works poorly then the benefits it provides when it works well (in theory this should not happen)

So basically, if you have a folder containing plain text files and nothing else then it will benefit from the compression... except the benefit in such a case is totally meaningless because you are not hurting for speed or space with plain text files. Any program, game, or OS folder that gets compressed does more harm the good, and any media folder is most likely containing mostly already compressed files which it harms. Even document folders are bad nowadays as modern document formats are compressed as well.

If microsoft had a tool that would automatically compress files on non SSD drives, test for read speed of compressed vs non compressed, and keep the faster one, then NTFS compression would have a use. But since no such tool exists then you might as well ignore the feature

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