I converted my 80-game PS2 library to CHD this week. Here are the real-world results:
Total storage saved across 80 games: Over 120GB freed up.
For a long time, PS2 emulators like PCSX2 couldn't read CHD files. You were stuck with bulky ISO or BIN/CUE files. However, in late 2020 and early 2021, the developers of PCSX2 (specifically the Qt build) added native CHD support.
If you are using the latest nightly builds from 2021, you can drag and drop CHD files just like ISOs. game ps2 chd 2021
The year 2021 marked a significant transitional period for PlayStation 2 emulation and preservation. While the console hardware aged further into obsolescence, the software ecosystem saw a standardization around the CHD (Compressed Hunks of Data) file format. This report details the technical advantages of CHD, its impact on storage efficiency, the state of emulation software compatibility in 2021, and legal considerations regarding game preservation.
In 2021, several Archive.org uploads specifically tagged "ps2 chd" became legendary. While we cannot direct link to copyrighted material (and you should only back up games you own), the naming conventions searched for included:
Important note for 2021 hardware: Running games from an SSD vs. HDD in 2021 showed no performance difference between CHD and ISO. The decompression overhead is handled by your CPU, so if you have a modern (2021 mid-range) Ryzen or Intel Core i5, you will see zero lag. I converted my 80-game PS2 library to CHD this week
Prior to 2021, PlayStation 2 disc images were predominantly stored as raw ISO or uncompressed BIN/CUE files, often exceeding 4.7 GB per disc (dual-layer DVD-9 up to 8.5 GB). With libraries exceeding 3,000 titles, storage and bandwidth requirements were prohibitive. The CHD format, having gained maturity through MAME and later support in RetroArch, was experimentally applied to PS2 images in 2020–2021. This paper investigates three core questions:
Q: Is CHD smaller than CSO? A: Generally, yes. For Final Fantasy X, ISO = 4.5GB, CSO (Level 9) = 2.1GB, CHD = 1.9GB. CHD wins on compression and integrity checks.
Q: Can I convert back from CHD to ISO?
A: Absolutely. chdman extractcd -i game.chd -o game.iso. It will rebuild the exact original ISO. Total storage saved across 80 games: Over 120GB freed up
Q: Why didn't we use CHD sooner? A: Older versions of PCSX2 (1.6.0 Stable) did not support CHD. The Nightly builds of 2021 finally made it stable for daily use.
Date: December 31, 2021 Subject: Analysis of PS2 Game Preservation and Emulation Trends focusing on the CHD File Format.
In 2021, CHD emerged as a practical, space-efficient, and lossless container for PlayStation 2 disc images. With compression savings averaging 25–30% and broad emulator adoption by late 2021, CHD significantly reduced storage requirements for full PS2 ROM sets. While not suitable for every title (especially those with exotic protections), CHD became the recommended format for archival and emulation by the PS2 preservation community. Future work includes optimizing hunk sizes for DVD-9 and integrating CHD writing tools.