I believe everyone in this forum knows what a file system means and that every windows user knows what FAT and NTFS means so I am not gonna start going into those.

Well, the NTFS (Windows NT file system) offers a few advantages over the good ol' FAT (File allocation table) file system one of which is the files and folders compression. This I have done quite a number of times to save disc space (and it really does save some disc space). i am using my computer as an example here. Consider my 35GB partition which is carrying my Windows Vista Operating sys and has less than 6GB (5.66GB to be exact) free space. I decided to run files and folders compression on the partition to recover som useful space in there. This I did and when the process finally finished, I found out that I have recovered more than 5GB of space which the files in my HDD were playing around with.

Well, this is a very good feature for anyone who is conscious about the space in his/her HDD. the lil' hitch in here (or so I thought) is that I felt that my computer's performance kinda came down a lil' bit. I kept wondering why. This happened after the files and folders compression was done.

Could it be that the files that where compressed, that it was not possible for the HDD read heads to read the files fast enough as it was doing before probably due to the files that were compressed? I just cannot figure out why this is happening. now, i am considering uncompressing the files and folders in that particular drive/partition.

Apart from that, during the time I was using my desktop (which I exchanged for this laptop taht I am using right now), I had three HDDs in there (240GB in all [80GB x 3). I have always noticed that during data transfer between partitions or individual HDDs, the compressed partitions transfer at a slower rate than the uncompresed ones by a big margin. Just think of a situation whereby an uncompressed HDD partition is able to transfer files with as much as 48MB/sec while the compressed on was transfering at lower than 15MB/sec. This is really annoying if you are my kinda person who is always moving large chunks of data within your computer and you have to wait for more than 20 mins for your PC to transfer a 10GB worth of data.

Well, I am still wondering whether the files and folders compression being offered by the NTFS file system is worth the trouble or did Microsoft make it a case of YOU CANNOT EAT YOUR CAKE AND HAVE IT? in which case you have to sacrifice performace in order to regain hard drive space.

The lag and general performance hit of using the file compression is because the processor has to decompress data before it can be used. Knowing M$ I'm sure they didn't put too much planning into what method was used to compress the files. Note that they didn't bother to put in any settings for compression. also from my experience WinXP forces a decompress/recompress cycle when copying from one compressed partition to another. this may simply be due to how the compression is carried out on the filesystem or may be poor planning on the developers.



With any sort of compression there will always be a performance hit just because of the necesity of decompression before use. this is true with all compression regardless of how fast the algorithm is or how little the data is actually being compressed. as a fairly good example of this. even with the command line Winzip will take longer to "unzip" a storage only zip file than a copy and bulk rename of an equivalent files.

Well, Microsoft should have thought about this during the development of this very technology which they incorporated into the NTFS file system. I think this is a kinda hitch on MS as they should have thought about this very issue. What I generally do now is that I only compress my backup partitions while leaving the root and installation partitions uncompressed.

I love how people always claim to "know M$" when in fact they do no research.

The Compress Old Files feature in Disk Cleanup compresses files that you haven't touched in 50 days. If you haven't touched it in 50 days, chances are you won't touch it in another long while, and if you do, you were patient enough already to dig it up. It's not meant to be super configurable, just convenient for a single purpose.


What do you want to do, heavily compress files?

There's a reason Microsoft uses .zip more often than NTFS compression. A lot of reasons, in fact. NTFS compression serves one purpose and one purpose only. Quit yammering.


That's because compression is implemented by NTFS, not by the volume manager. It's to be expected. Zip your files or use a sparse archive format if you don't like it.

And don't call me a marketroid or any dumb *BLEEP* like that. I'm not selling you anything, I'm just sick of people not knowing what they're talking about. It's driving me bat *BLEEP* insane to see this kind of garbage top Google every single time.

This post has been edited by reinux: Jan 26 2008, 04:07 AM

I've had bad experiences with NTFS file compression as well. As Hard Disk Drive prices continue to plummet, I would suggest purchasing a new HDD, as much of a generic answer as that is. You could also backup files that you are not going to change and that you don't access often onto DVD's; that always helps keep my 80GB HDD from filling up. Unless you're not concerned about performance at all on your PC (which I know everyone is), I would not manually compress your entire HDD because of the performance hit. As reinux mentioned, you should archive your files (though use 7-zip, it's much more efficient than ZIP) if you're unable to follow any of my other tips.

I agree. Now how do you expand/decompress multiple files and folders w/o having to go through windows and set the attributes for each and every one?!? I've yet to figure out how to do this!

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Ok, I figured out a solution to my own question...there may be a better one out there but here goes. Say you have a directory with ten folders in it, all having multiple compressed files within each. Create a dummy text file in this folder and give this new file the 'compressed' attribute. Then select this file and the other folders, right-click properties, and clear the box for compression. Windows will ask if you would like to decompress all files and subfolders of the selected folders. Just click yes and you are done.

NTFS compression could have been useful if they had used a decent compression algorithm like the famous Oberhumer LZO which decompresses at about 20 MB/s.

On a Pentium 133.

On a fossilized Athlon from 2005 it does about 200 MB/s.

I'll let you check it out on a Core 2. It's faster than a modern harddrive (even when compressing). Compression is decent, too.

The other thing is that the cache should cache compressed data which would double the size of your disk cache. But it doesn't.