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ImminentFate edited this page Feb 10, 2018 · 18 revisions

Important Information

This has gained a lot more traction than I thought it would, so there are a few things that need to be cleared up:

  • What Operating Systems does this work on? - CompactGUI uses the new algorithm introduced in Windows 10. Therefore, this program won't work on older OSes. This program will not work on Linux or OSX either.

  • I compressed the folder but TreeSize/Spacesniffer still show it as taking up the full space? Why? - Those programs can only read the Folder's size, not the size taken on disk, because that is much harder to read. To see this information right click the folder and go to properties.

  • My SSD's free space doesn't seem to increase after compressing - The folders are still compressed, this seems to be an issue with how the SSD size is being reported in Windows. Open the drive in Explorer, then press Ctrl + A to select everything, then Right Click > Properties and check the size on Disk there to see if there's a difference.

Edit: Windows has a rather ugly bug where a file that is >4GB in size that gets compressed will be blatantly inaccurate. For example, compact.exe will compress a 4.5GB file down to 1.2GB. In reality, the actual compressed size is (4.5GB - (4GB + 1.2GB)) = 0.3GB. So for games and programs that contain single massive files over 4GB (virtual disks, etc.) you cannot trust the results from compact.exe (which also makes CompactGUI inaccurate) nor can you trust the file's properties window. You can only see the true size by checking the hard drive's size before and after compression. I am working on a stopgap fix for this until Microsoft sorts their bug out, but it requires a complete rewrite of the program's inner workings, so it will take time.

  • Does this affect performance? - Yes and No. It's compression, so extra CPU power is required to decompress the program files as they're needed, however the XPRESS algorithm is highly efficient and designed for minimal CPU overhead. Any reasonable CPU will have minimal to no performance impact, and those using slower HDDs may even see a performance improvement as the smaller files can be transferred to the CPU much faster for processing. See the Microsoft doc here

  • I copied/moved the compressed folder but it's no longer compressed. Why? - Compression depends on the files staying exactly where they were. If you move them, they'll get decompressed at the new location. If you copy them, the copies will get decompressed.

Limitations

  • This compression may not be permanent - it's a limitation of Windows itself, that the Xpress and LZX functions cannot be run live on new files that are added to the compressed folders. What this means is that over time, with updates to your games, you will experience compression decay; the folder will slowly but surely grow in size until it is back to its original size. You can somewhat get around this by first running Compact on any folder you choose, then run compact.exe /c /s on the folder afterwards which will mark it so that future files will get compressed

    • Note however that this will not use the Xpress algorithm, so the compression of new files won't quite be as significant. This is still better than using the default NTFS compression in Windows ("compress this folder to save space"). HOWEVER, THIS WILL NOT COMPRESS FILES THAT ARE UPDATED IN THE FOLDER. ONLY NEW FILES ADDED WILL BE COMPRESSED.

  • Some games don't like this compression - Guild Wars 2 is an example, it compresses down massively, but as soon as you run the game it will hang as it uncompresses the entire game again before it lets you play it.

  • Copying files to other systems or syncing to online services will not be compressed - This means that you can safely use this on OneDrive and Google Drive folders, as only the local variant will be compressed. If you copy the files to another drive or computer, they will be decompressed. However If you're compressing files on an external drive, note that those files will only be able to be read on a Windows 10 PC until they're uncompressed again.

  • Works on Windows 10 Only - The features used in this program were only introduced in Windows 10. Earlier OSes will not be able to run this program.

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