: While similar to the older .cso format, CHD generally offers better compression ratios and is more efficient for modern emulation hardware. Accessing Collections on the Internet Archive

"psp" AND "chd" AND (collection:software OR collection:emulation)

: CHD often achieves smaller file sizes than CSO while remaining just as compatible with modern emulators.

psp-chd-zstd-redump-part1 directory listing - Internet Archive