If you do not own the discs, many "abandonware" archives and ROM repositories offer pre-compressed libraries. Look for these keywords:
Only natively supported by Dolphin and emulators built on its core. Compression Comparison: How Much Space Can You Save?
| Format | Compression Ratio | Lossless | Native Support | Best For | | :--- | :--- | :--- | :--- | :--- | | | Up to 60-80% reduction | Yes | Dolphin (Latest) | General use & emulation | | NKit | Up to 70% reduction | Yes | Dolphin (via conversion) | Restoration & fixing ROMs | | GCZ | 50-70% reduction | Yes | Dolphin (Legacy) | Older emulator builds & Wii backups | | CISO | 20-30% reduction | Lossy | Fewer emulators | Older modded consoles | | ISO/GCM | None (1.4 GB) | N/A | All | Archival & debugging | | WBFS | 30-50% reduction | Lossy | USB loaders | Wii backups on original hardware | gamecube roms highly compressed
Click and choose where to save your new, highly compressed file.
The choice of format depends on whether you intend to play the games on an emulator (like Dolphin) or original hardware (Wii/GameCube). Product information | Support | Nintendo UK If you do not own the discs, many
Click Convert . Dolphin will output a highly compressed file in the same folder, allowing you to delete the bulky 1.35 GB ISO safely. Space Savings: What to Expect
(And always check your local laws—owning ROMs of games you don’t have physical copies of is piracy.) | Format | Compression Ratio | Lossless |
If a game like Animal Crossing only required 30 MB of actual game data, Nintendo filled the remaining 1.32 GB of the disc with randomized "dummy" data or zeros. This junk data was used to optimize laser reading speeds on the original console hardware and deter piracy.
Smaller than standard ISOs; supported by older emulators.