To understand how a 4GB game shrinks to 400MB, you need to understand how PS2 discs were formatted. Many retail PS2 games contained "dummy data"—essentially blank files used to fill up the physical DVD so the console's laser could read the disc more efficiently.
PCSX2 is the gold standard for Windows, Linux, and Mac. For Android devices, AetherSX2 or NetX2 offer excellent performance. Highly Compressed Ps2 Games Under 500mb
CHD uses a mixture of LZMA for data tracks and FLAC for audio tracks . This hybrid approach is superior to other compression methods. Gzip (the standard) uses DEFLATE compression, which generally saves less space than LZMA for general data. Furthermore, neither DEFLATE nor LZMA performs as well as FLAC for compressing audio. Because PS2 games contain a lot of sound effects and music, CHD’s combination is far more efficient. To understand how a 4GB game shrinks to