Modern formats like CHD (Compressed Hunks of Data) or PBP (PlayStation Portable) can reduce file sizes by roughly 30–40% without losing any game data.
This is the biggest reason PSX games could be compressed so drastically. Developers in the PS1 era often used a cheap trick to speed up load times: they placed the game data on the . psx highly compressed roms fixed
To understand the "fix," one must first understand the compression. A standard PS1 ISO file (the raw data ripped from a CD) averages between 500 to 700 megabytes. In the days of 4GB hard drives, storing a library of games was impossible. Modern formats like CHD (Compressed Hunks of Data)