How One Gamer Saved 380GB and Boosted Game Speeds with CompactGUI

Here’s a story about a gamer “IridiumIO“ who managed to compress 60 Steam games and save 380 GB of space — all while making them launch faster than before.

How is that even possible? Simple: on a regular hard drive, decompressing data in real time using a modern CPU can actually be faster than reading raw uncompressed data at 7200 RPM. The magic trick behind this feat is an underrated Windows tool called CompactGUI.

Compression That Speeds Things Up

You’d think that compressed files always load slower, right? Not in this case. On modern hardware, CPUs can decompress files into RAM faster than mechanical drives can read large chunks of data.

That’s the principle behind CompactGUI, a graphical front-end for Microsoft’s built-in compact.exe command. Microsoft quietly upgraded this tool in Windows 10 with new compression algorithms (XPRESS4K, XPRESS8K, XPRESS16K, and LZX), then promptly buried it in the system—until the community rediscovered it.

How CompactGUI Works

CompactGUI gives compact.exe a modern, one-click interface. You simply:

1. Point it to a game folder (e.g., C:\Program Files (x86)\Steam\steamapps\common\Doom)
2. Choose your preferred algorithm
3. Hit Compress

Windows will then compress all game files transparently — meaning your games still run normally, appear in File Explorer as usual, and take up 30–60% less space.

When you launch a game, Windows automatically decompresses files in RAM, on the fly. The result? Smaller files, same experience, no visible slowdown.

The Four Compression Algorithms Explained

CompactGUI lets you choose between four compression methods. Each offers a tradeoff between speed and compression ratio:

• XPRESS4K – Fastest but least efficient (~50% compression). Default and safest for most users.
• XPRESS8K – Better ratio with minimal CPU cost. Often the best balance on modern PCs.
• XPRESS16K – Stronger compression (~57%), but slightly heavier on CPU.
• LZX – The most powerful (up to 66% compression), but CPU-intensive. Best for high-end rigs.

For example, compressing a 46.6 MB file:

• LZX → 15.7 MB
• XPRESS16K → 20.1 MB
• XPRESS8K → 21.1 MB
• XPRESS4K → 23.0 MB
• Old NTFS compression (LZNT1) → 26.2 MB

Clearly, these newer algorithms are far more efficient, but since using them via PowerShell is tedious, CompactGUI makes the process accessible to everyone.

Real-World Compression Results

Here are some real-world examples reported by the CompactGUI community:

• Cyberpunk 2077 – 102 GB → 65 GB (–37 GB saved)
• Red Dead Redemption 2 – 119 GB → 74 GB (–45 GB)
• Elden Ring – 49 GB → 27 GB (45% smaller)
• Call of Duty: Modern Warfare II (2022) – 125 GB → 82 GB (–43 GB)
• The Witcher 3: Wild Hunt (Next-Gen Update) – 73 GB → 44 GB (–29 GB)
• Stardew Valley – 1.4 GB → 0.8 GB using LZX

Even more impressive: performance barely changes. Most users report identical gameplay and loading times. In fact, players with traditional HDDs often notice slightly faster load times because the system reads less data from disk — easily offsetting the CPU cost of decompression.

Why It Works So Well

Games store textures and audio in compressed formats like DDS, OGG, or MP3. But other assets—scripts, configs, shaders, or level data—are often uncompressed. That’s where XPRESS and LZX shine.

Modern CPUs handle LZW-based decompression (used in LZX) with ease, especially on dual- or quad-core systems. XPRESS algorithms are even lighter, so the small CPU cost is more than compensated by the faster disk access.

The Big Catch: DirectStorage

There’s one major caveat: DirectStorage.

This Windows 11 feature allows games to load assets directly from your SSD to the GPU, bypassing the CPU. It dramatically cuts load times on NVMe drives—but it doesn’t play well with NTFS compression. Games using DirectStorage may crash or suffer degraded performance if their files are compressed.

In short:

• If you’re gaming on HDDs or SATA SSDs, CompactGUI is fantastic.
• If you’re on Windows 11 with a fast NVMe SSD and playing modern AAA titles that support DirectStorage — skip it.

How to Install CompactGUI

You can grab it directly from GitHub Releases, or install it via Winget:

winget install CompactGUI

Then:

1. Launch CompactGUI
2. Select your game folder
3. Pick an algorithm (XPRESS8K is a great starting point)
4. Click Compress

CompactGUI shows a progress bar, estimated time, and live compression ratio. Once done, you’ll instantly free up space without affecting your games.

To restore a folder, simply click Uncompress — everything returns to its original state.

Smart Features You’ll Love

• Background Monitoring – Automatically compress new games as they’re installed.
• Right-Click Menu Integration – Add “Compress with CompactGUI” to Windows Explorer for instant access.

It’s simple, smart, and works invisibly.

A Hidden Windows Gem

It’s almost funny: Microsoft built powerful compression algorithms worthy of WinRAR, added them to Windows 10, and then… forgot about them.

Thanks to the community (and a developer named Lorenper, who shared CompactGUI), these tools are finally getting the attention they deserve.

Final Thoughts:

CompactGUI is one of those rare hidden gems that delivers real, measurable benefits with zero downside for most gamers. If you’re tired of seeing your Steam library eat terabytes of disk space, or you’re still rocking a mechanical hard drive, this lightweight utility can save hundreds of gigabytes—and maybe even make your games load faster.

So before you buy another SSD, try compressing what you already have. You might be surprised by how much space—and speed—you can gain.