: As noted by the RPCS3 team, emulators typically support decrypted ISOs . Highly compressed files found online are often already decrypted for ease of use. 2. Formats and Compatibility

The Ultimate Guide to Highly Compressed PS3 ISO Games: Gaming on a Budget

: A single-file disc image that mimics the original physical Blu-ray.

: While the archive is small, the game must be extracted to its full size to run on hardware or emulators.

Security & technical risks

If you have a jailbroken PS3 (using HEN or Custom Firmware), you can play games directly from an external USB drive. But older USB 2.0 drives are slow. Highly compressed ISOs, once extracted, often load faster because the physical head reads less "junk data."