If you are familiar with ROM formats, you likely know ISO and CSO. ISO is a raw, uncompressed disc image. CSO (Compressed ISO) was the standard for PSP emulation for years, offering decent compression. is a newer, superior format originally developed for MAME (Multiple Arcade Machine Emulator) to compress arcade hard drives and CD-ROMs.

Finding these files is straightforward. By searching "PSP CHD Internet Archive" or looking for specific "Redump" collections on the site, users can find verified, high-quality dumps of their favorite titles. These files are typically pre-tested and ready for use in popular emulators. It is important to remember, however, that these archives should primarily be used to back up games you already own physically, ensuring your library remains accessible even as hardware ages.

: Unlike .zip or .rar archives, modern emulators like PPSSPP (v1.17 or newer) can play CHD files directly without decompressing them first.

(Compressed ISO). However, CSO often introduces performance overhead due to its use of GZip compression. The emergence of CHD as a standardized, lossless alternative has revolutionized how these libraries are stored and accessed on platforms like the Internet Archive 2. Technical Analysis: The CHD Format

The Ultimate Guide to PSP CHD Files and the Internet Archive