Iso To Zso Converter -

Easiest for end-users.

Note: This uses maxcso internally.

Assumption: you have a valid ISO and a converter tool installed that supports zso output.

  • Choose settings (defaults if unsure):

  • Run conversion (example command pattern):

  • Verify:

  • Optimize (if needed):

    • Created by the developer of the PPSSPP emulator (Henrik Rydgård), ziso is the official tool. It is lightweight, fast, and open source.

  • Copy your newly created .zso file into the ISO folder.
  • Disconnect and test the game on your PSP.

    • Using MaxCompress as an example:

    That’s it. Your game now loads faster and eats less space. iso to zso converter

    You may have heard of CHD (Compressed Hunks of Data), another popular compressed format used by MAME, Dreamcast, and PSX emulators.

    | Feature | ISO | ZSO | CHD | | :--- | :--- | :--- | :--- | | PS2 Support (PCSX2) | Yes | Yes | No (alpha) | | PSP Support (PPSSPP) | Yes | Yes | No | | Compression Ratio | 0% | 40% avg | 50% avg | | Speed | N/A | Very Fast | Moderate | | Lossless | Yes | Yes | Yes |

    Verdict: For PSP and PS2 emulation in 2025, ZSO is the winner due to native emulator support and fast decompression. For PS1 and Dreamcast, use CHD. For raw archives, stick with ISO. Easiest for end-users