: CHD achieves better compression than CSO through its combination of LZMA for data and FLAC for audio, making it superior for archival purposes.
: CHD files can reduce PS2 ISO sizes by 30% to 60% . For example, a 1GB ISO can sometimes be compressed down to just 55MB.
As of early 2026, has become the definitive storage format for PlayStation 2
for %%i in (*.iso) do chdman createcd -i "%%i" -o "%%~ni.chd" ps2 chd roms upd
The transition to CHD for PS2 roms is driven by its efficiency and growing toolset:
The table below outlines how CHD compares directly against traditional uncompressed and compressed disc image formats: ISO / BIN-CUE CHD (Compressed Hunks of Data) Uncompressed Compressed Highly Compressed Data Integrity Lossless (typically) 100% Lossless Average Space Saved 20% – 45% 30% – 60% Multi-track CD Support Requires separate CUE Poor / Variable Fully supported in one file Emulator Compatibility Widespread Native in modern emulators How to Convert PS2 ISOs to CHD
Converting ISOs/BIN/CUEs to CHD typically reduces file sizes by 30% to 60% . A 4GB game might become 2GB, allowing you to double your collection size on the same hard drive. : CHD achieves better compression than CSO through
(Docker container with web UI): For users running Unraid or Docker environments, this project offers a full web interface for bulk conversion, automatic game name lookup by disc ID, bad dump detection, and optional MD5 verification against Redump databases.
"Upd" often refers to obtaining the latest revisions of games or ensuring they are in the correct format for modern emulators.
: Smaller file sizes mean modern operating systems can read and stream data into system RAM much faster, occasionally boosting performance on modern hardware architectures. Modern Emulator Compatibility As of early 2026, has become the definitive
: The emerging Iris PS2 emulator supports CHD, CSO, and ZSO formats in addition to standard ISO and BIN/CUE. This multiplatform emulator (Windows, macOS, Linux) is actively under development and represents the growing ecosystem embracing compressed formats.
: PS2 games average a 40% to 60% reduction in total file size when converted from standard .ISO to .CHD .