In a "highly compressed" rip, the internal structure of the files is altered. If the game attempts to load a texture or audio file that has been butchered by compression software, the emulator cannot decrypt the hash. The result is not just a smaller file size, but a broken game that cannot pass its own internal boot checks.
Historically, users had to extract ISO files into complex folder structures. As of early 2026, RPCS3 supports direct loading of decrypted ISOs . This allows you to keep games in a single-file format, which is easier to manage than thousands of loose files. rpcs3 highly compressed games work