The PS3’s internal hard drive (especially original models) is SATA I (150 MB/s). Highly compressed ISOs are stored as "PKG" or "folder format" files. When extracted, the smaller data footprint can sometimes lead to faster loading times because the drive heads have less distance to travel.
Safer, legitimate alternatives:
A pre-patched ISO means someone already applied: ps3 iso games highly compressed patched
However, patching without your knowledge can introduce instability, missing content, or even malware if the source is untrustworthy. Many “patched” releases from forum users are poorly tested. The PS3’s internal hard drive (especially original models)
There is a legitimate way to compress PS3 ISOs, but it isn't magic. Standard ISO formats cannot be compressed heavily because the data is already optimized. However, converting an ISO to a "JB Folder" (Jailbreak Folder format) allows for file compression. A pre-patched ISO means someone already applied:
By converting an ISO to a folder format, you can sometimes save space, but usually only around 10-20%, not the 90% reduction claimed by shady download sites.