Free app based on official Microsoft tech saves huge Windows space with no performance loss

It is no secret that modern games eat up a ton of disk space. Previously, it was generally game assets like high-resolution textures and 3D models with super-high polygon counts that had the most impact. However, modern games also incorporate ray tracing, and ray tracing shaders are a massive hog when it comes to storage space.

For those tight on space, thankfully, there are compression tools available out there and one of those happens to be CompactGUI. The utility is based on Windows' own compact.exe command line tool that helps optimize for storage space by compressing and decompressing files and folders on NTFS file systems.

Thus, CompactGUI, as the name suggests, provides a simple GUI solution for compact-based commands. The developer of the app has explained how it works and claims that there is little to no performance loss as a consequence:

Windows 10 introduced a little-known but very useful tool called compact.exe that allows one to compress folders and files on disk, decompressing them at runtime. With any modern CPU (I have tested as old as an i3-370M from 2010 with negligible impact), this added load is hardly noticed, and the space savings are of most use on those with smaller SSDs.

As program folders and games can be shrunk by up to 60%, this has the added bonus of potentially reducing load times - especially on slower HDDs.

Besides the talk of performance, the dev also claims significant disk space savings for both games as well as productivity apps. For example, in the case of ARK-Survival Evolved, a 54% or 0.54x compression ratio has been claimed. Meanwhile, in the case of Adobe Photoshop, that promise gets even bigger at 50.6% or 0.506x:

• Reduce the size of games (e.g. ARK-Survival Evolved: 169 GB > 91.2 GB)
• Reduce the size of programs (e.g. Adobe Photoshop: 1.71 GB > 886 MB)

Recently, XDA tested CompactGUI in some of the supported games to see how good this free tool is.

The results were generally great and in some cases users can expect to save a lot. The outlet also says that it did not note any significant performance loss or visual difference post-compression.

Baldur's Gate 3 saw significant savings especially in the case of XPRESS compression algorithms. XPRESS4K is the default one that Windows uses, and it is also the fastest, so it can provide a baseline.

Meanwhile, L777-based Lempel-Ziv Extended (LZX) compression engine is a universal lossless (compact) data compression algorithm for NTFS. This, however, also requires more processing and memory bandwidth than the XPRESS algorithms.

Game	Compression type	Size before compression	Size after compression	Compression ratio
Baldur's Gate 3	XPRESS4K	142.62GB	130.78GB	0.92x
Baldur's Gate 3	XPRESS8K	146.18GB	129.92GB	0.89x
Baldur's Gate 3	XPRESS16K	145.9GB	129.78GB	0.89x
Baldur's Gate 3	LZX	152.71GB	134.54GB	0.88x

Counter-Strike 2 was next and it offered even bigger savings in terms of percentages:

Game	Compression type	Size before compression	Size after compression	Compression ratio
Counter-Strike 2	XPRESS4K	39.44GB	29.34GB	0.74x
Counter-Strike 2	XPRESS8K	36.18GB	26.28GB	0.73x
Counter-Strike 2	XPRESS16K	37.73GB	28.13GB	0.75x
Counter-Strike 2	LZX	38.17GB	27.04GB	0.71x

Finally, a bunch of miscellaneous titles were also tested:

Game	Compression type	Size before compression	Size after compression	Compression ratio
Little Kitty: Big City	XPRESS16K	13.76GB	6.34GB	0.46x
Little Kitty: Big City	LZX	13.43GB	5.44GB	0.40x
Cities: Skylines	XPRESS16K	13.06GB	7.08GB	0.54x
Cities: Skylines	LZX	13.27GB	6.3GB	0.47x
Half-Life: Alyx	XPRESS16K	72.93GB	61.6GB	0.84x
Half-Life: Alyx	LZX	72.52GB	58.08GB	0.80x

Hence, there seems to be a pattern. It appears that AAA titles, which are very heavy in visual effects, saw the least savings, and this implies that the default compression in such situations must already be quite efficient. Regardless, there are still situations where a tool like CompactGUI can help save lots of space.

If you wish to try it out, you can head over to the app's GitHub repo here to download it. Recently, the app was updated to use .NET 9 so you will prompted to download that. CompactGUI author, though, has cautioned not to try it in case of DirectStorage titles since they bypass the CPU and hence, the utility wouldn't be of much help.

Source: XDA