A modern Steam library eats 500GB before anyone notices. Cyberpunk 2077 alone claims 62GB, Call of Duty pushes past 200GB, and Baldur’s Gate 3 asks for 150GB on install. The usual response is to uninstall the games nobody has touched in months, but that means redownloading later on connections that are not always fast or unmetered. Game Compressor, the tool XDA covered when a user freed 300GB without deleting anything, is CompactGUI, an open-source front end that wraps Windows’ built-in NTFS transparent compression and shrinks installed games in place, often by 30 to 60 percent, with Steam none the wiser. The catch is that CompactGUI is not always the right fit for every setup. It has known performance issues on very large folders, its Visual Basic code shells out to compact.exe instead of calling the Win32 API directly, and games using DirectStorage on Windows 11 actively lose performance when their assets sit compressed on disk. We tested seven Game Compressor alternatives on Windows 11 that either do the same in-place compression differently, or attack the storage problem from another angle entirely.
Quick comparison
| App | Best for | Free plan | Starting price | Standout feature |
|---|---|---|---|---|
| Compactor | Direct NTFS compression via the Windows API | Yes | Free | Rust engine that calls Win32 directly, no compact.exe shim |
| Windows compact.exe | Scriptable command line, no install | Yes | Free with Windows | Ships in every Windows 10 and 11 build since 2016 |
| WizTree | Finding the biggest games before compressing | Yes | Free for personal use | MFT scan finishes an entire NTFS drive in seconds |
| TreeSize Free | Detailed reports and per-folder drilldowns | Yes | Free personal, Pro from $59.95 | Sortable table plus bar chart of every folder |
| WinDirStat | Fully open-source treemap visualisation | Yes | Free (GPLv2) | Colour-coded treemap of every file on disk |
| Steam Library Manager | Bulk-moving games to a bigger drive | Yes | Free | Drag-and-drop between multiple Steam libraries |
| 7-Zip | Archiving cold games for later reinstall | Yes | Free (LGPL) | LZMA2 shaves another 20 to 30 percent off a paused game |
Why people leave CompactGUI
Four patterns come up in Steam forums, Reddit, and the tool’s own GitHub issues. The first is speed on very large folders. Compactor’s README calls this out directly, noting that CompactGUI shells out to compact.exe rather than calling the Windows API, so a 100GB folder can take an unusually long time to scan and re-verify.
The second is DirectStorage. Newer Windows 11 titles that ship with the DirectStorage API stream assets straight from the SSD to the GPU, and files that first have to be decompressed by the CPU into RAM defeat that pipeline. Compressing those specific games slows loads instead of helping them.
The third is anti-cheat friction. A handful of kernel-level anti-cheat systems occasionally flag files whose on-disk block layout does not match what they expect after an update, which sends users hunting for the compression status of every affected folder. The fourth is workflow. Every Steam update writes new uncompressed files, so anyone relying on CompactGUI without the watchlist re-runs the scan by hand each patch day.
The alternatives
Compactor: best for direct NTFS compression via the Windows API
Compactor by Freaky is the closest direct alternative to CompactGUI on the technical merits. It is written in Rust and calls the Win32 compression API directly instead of spawning compact.exe, which fixes the “slow on very large folders” complaint that dogs CompactGUI. The four XPRESS levels and LZX are all exposed, the front end is an embedded web view, and the app opens no network ports.
Where it falls short: The project has not seen a substantive update since 2020 and the UI shows its age. There is no watchlist for automatic re-compression after Steam updates.
Pricing: Free and open source (Rust, embedded web view).
Vs Game Compressor: Faster on large libraries and closer to the Windows API. Missing the watchlist and the recent UI polish CompactGUI added in version 3.
Download: github.com/Freaky/Compactor
Bottom line: Pick Compactor if the CompactGUI slowness on large game folders is the specific problem you hit.
Windows compact.exe: best for a scriptable command line with no install
Windows compact.exe is the built-in Microsoft tool that CompactGUI and Compactor both wrap. Running compact /c /s /a /i /exe:LZX "C:\Program Files (x86)\Steam\steamapps\common\Game Name" compresses a single game folder with the LZX algorithm and skips files that are already compressed. It works on any NTFS drive since Windows 10 build 1809, ships with Windows 11, and returns the same compression ratios as the GUI tools because it is the same underlying feature.
Where it falls short: No progress bar, no automatic algorithm selection, no watchlist. You need to know which algorithm suits which game type, and re-running after each Steam update is a manual scripting job.
Pricing: Free, included with Windows 10 and Windows 11.
Vs Game Compressor: Same engine, zero install, but zero hand-holding. Ideal for a scripted setup on a homelab or a shared machine.
Download: learn.microsoft.com/windows-server/administration/windows-commands/compact
Bottom line: Pick compact.exe if you already script Windows admin tasks and would rather write a batch file than install a GUI.
WizTree: best for finding the biggest games before you compress anything
WizTree reads the NTFS Master File Table directly, which lets it scan a full 2TB drive in seconds instead of the minutes a directory walker needs. That speed matters when the goal is triage: figure out which four or five games account for 80 percent of a Steam folder, then decide whether to compress them, move them, or uninstall the ones you have forgotten.
Where it falls short: MFT scanning only works on local NTFS drives. Network shares and non-NTFS volumes fall back to the same slow enumeration everything else uses.
Pricing: Free for personal use. WizTree Enterprise from $12 per user per year for commercial licences.
Vs Game Compressor: Different job. WizTree tells you where the bloat is, CompactGUI removes it. Best used together.
Download: wiztree.co.uk
Bottom line: Pick WizTree as step one before running any compressor, so you spend CPU time on games that actually matter.
TreeSize Free: best for detailed folder reports and drilldowns
TreeSize Free from JAM Software presents a sortable table view of every folder with size, file count, allocated space, and last-modified date in one screen. Where WizTree optimises for a fast overview, TreeSize gives you the drilldown for a specific drive: expand steamapps, sort by size, and see the exact breakdown of textures, shaders, and cached shader files inside each game.
Where it falls short: The Free tier lacks scheduled scans, the deduplicate finder, and the search-in-archives feature. Some views nudge you toward the Pro upgrade.
Pricing: Free for personal use. Pro from $59.95 one-time, Business from $99.95.
Vs Game Compressor: A reporting tool, not a compressor. Complements CompactGUI or Compactor by explaining what each install actually contains.
Download: jam-software.com/treesize_free
Bottom line: Pick TreeSize Free when you want a full accounting of a drive before deciding what to shrink and what to remove.
WinDirStat: best for a fully open-source treemap
WinDirStat lays out every file on a drive as a colour-coded rectangle sized by disk usage, so a single glance shows that Modern Warfare’s asset cache is a giant orange block dominating the map. It is GPLv2, has no commercial tier, and treats every drive the same because it does not depend on NTFS-specific tricks.
Where it falls short: Slower than WizTree on large drives because it walks the directory tree the classic way. The UI has not been meaningfully updated in years and does not scale well on high-DPI displays.
Pricing: Free and open source (GPLv2).
Vs Game Compressor: A visualiser, not a compressor. Better than WizTree when you want a true open-source alternative and do not mind waiting for the scan.
Download: windirstat.net
Bottom line: Pick WinDirStat if the license matters and the visual treemap is what you find easier to reason about.
Steam Library Manager: best for moving games to a bigger drive instead of compressing them
Steam Library Manager (SLM) by RevoLand handles the case where compression is not the answer, more physical storage is. It lets you set up multiple Steam library folders across drives and then drag-and-drop games between them, including bulk moves that would otherwise mean one right-click “move install folder” per title inside the Steam client.
Where it falls short: The project’s release cadence has slowed, and it can conflict with the Steam client if both try to touch the same library at once, so you need to close Steam during bulk moves. Steam’s own built-in move-install-folder covers single moves fine.
Pricing: Free and open source.
Vs Game Compressor: Solves the same problem (running out of C: drive) with a completely different approach. Move rarely-played games to a slower HDD instead of compressing them on the SSD.
Download: github.com/RevoLand/Steam-Library-Manager
Bottom line: Pick SLM if you already have a second drive and would rather relocate than recompute.
7-Zip: best for archiving cold games you might reinstall later
7-Zip attacks the problem from the opposite end. Instead of transparent in-place compression, it packs an entire installed game folder into a single .7z archive with LZMA2, typically shaving another 20 to 30 percent off what NTFS compression alone can manage. The trade-off is that Steam no longer sees the game at all, so you use this for the pile of titles you have finished and want to shelve rather than uninstall.
Where it falls short: Not transparent. The game will not launch until you extract the archive, which takes minutes on a large title, and Steam still thinks the install is missing so re-adding it to the library needs manual work.
Pricing: Free and open source (LGPL).
Vs Game Compressor: Different use case. CompactGUI keeps games playable at a smaller size; 7-Zip archives games that are not playable but that you refuse to redownload.
Download: 7-zip.org
Bottom line: Pick 7-Zip for cold storage of finished games on a slow drive or a NAS, not as an everyday compressor for your active library.
How to choose
Pick Compactor if you already tried CompactGUI and hit the slow-on-large-folders wall. It is the closest technical alternative and it fixes exactly that complaint.
Pick Windows compact.exe if you script your Windows setup and would rather write a batch file than click through a UI. It is the same engine, and zero install is a real feature on shared machines.
Pick WizTree as step one every time, before you compress anything. Compressing the ten small games in your library saves nothing worth the CPU time; compressing the three biggest ones is 90 percent of the win.
Pick TreeSize Free when you want the numbers behind the visualisation, and WinDirStat if the license matters more than the scan speed.
Pick Steam Library Manager if the actual answer is a second drive rather than smaller files, and you own a couple of hundred games spread across libraries.
Pick 7-Zip for cold storage of games you have played through and want to shelve without redownloading later.
Stay on Game Compressor / CompactGUI if you want a modern GUI with the watchlist that recompresses new files after each Steam update, and your game library is not so large that the known folder-scan slowdown hurts. Version 3’s new UI and XPRESS/LZX selector are still the most polished workflow for a home Windows machine.
FAQ
Does compressing games with Game Compressor slow them down? On mechanical hard drives and older SATA SSDs, compressed games usually load the same or slightly faster because there is less data to read off disk and modern CPUs decompress XPRESS in microseconds. On NVMe SSDs the difference disappears in most titles. The one exception is games that use the DirectStorage API on Windows 11, where compressed on-disk assets defeat the point of streaming straight to the GPU.
Is Game Compressor safe for Steam and anti-cheat? Yes for most games. NTFS transparent compression is a filesystem feature, so applications see the same files, and Steam’s integrity check does not flag them. A small number of kernel-level anti-cheat systems occasionally misbehave after Windows updates, so if a specific competitive title starts refusing to launch, decompress that one folder as a first troubleshooting step.
What is the best free alternative to Game Compressor? Compactor is the closest like-for-like tool, and Windows compact.exe is the built-in command line if you do not want any install. For finding what to compress first, WizTree is faster than anything else on NTFS drives.
Can I compress games on an SSD or only on an HDD? Both. The compression happens in the NTFS filesystem, not in the drive firmware, so any NTFS-formatted volume works. On SSDs the space savings are the point; on HDDs you also get a modest load-time improvement because the disk reads less data.
Does the compression survive a Steam update? Existing compressed files stay compressed, but any new or replaced file that Steam writes during an update lands uncompressed. CompactGUI’s watchlist feature detects those new files and recompresses them automatically; Compactor, compact.exe, and manual runs need you to re-run the compression by hand.
Is there a Mac or Linux equivalent for compressing installed games? Not for the transparent NTFS approach. APFS on macOS and Btrfs/ZFS on Linux both support transparent compression, but the tooling is different and the workflow for Steam libraries there is closer to “move to a bigger drive” than “compress in place.” Steam Library Manager works on those platforms for the move workflow.
