Highly compressed versions often use the .CSO format, which can reduce the file size by roughly 1–10% without losing game quality, though it may result in slightly longer loading times or occasional choppiness in cutscenes.
: Extremely small "highly compressed" versions (e.g., under 100MB) often achieve their size by permanently stripping data, such as removing commentary, background music, or cinematic cutscenes. FIFA 11 Review - IGN fifa 11 psp highly compressed
: Unlike ZIP files that must be fully extracted before use, the PSP or an emulator like PPSSPP decompresses CSO data "on the fly" while the game is running. Performance Trade-offs While high compression saves space, it is not without cost. Highly compressed versions often use the