For GameCube ROMs (ISOs), the "proper" way to achieve high compression while maintaining full compatibility with the Dolphin Emulator is using the RVZ format.
Final verdict:
Happy emulating—legally and safely.
Preserve the cube. Play the cube. But don't let file size obsession ruin The Wind Waker’s iconic soundtrack. Compress wisely.
Cause: Save states are tied to exact byte offsets. Compressing changes those offsets.
Fix: Use in-game saves (memory card). Save states only work if you compress before starting the game. gamecube rom highly compressed
When you see a "highly compressed" ROM, it is almost always a GCZ file or a scrubbed ISO where the empty padding has been removed.
Nintendo GameCube discs originally held approximately 1.459 GB of data. While this seems small by modern standards, a full library can quickly consume terabytes of storage. Fortunately, because GameCube discs were often "padded" with junk data to fill the physical capacity, these files are highly compressible. For GameCube ROMs (ISOs), the "proper" way to
Settings: The default settings are generally best. While you can increase the compression level (e.g., LZMA), it will take longer to compress and may offer diminishing returns on space.