If you are using custom firmware (CFW) or a PC emulator like Citra, your SD card or hard drive fills up fast. That is where come in.
Reports regarding "highly compressed" Nintendo 3DS games typically refer to two legitimate technical processes: (removing filler data) and container conversion (converting .3ds to .cia ). While these can reduce file sizes by up to 45%, any external site claiming "ultra-compressed" games (e.g., a 4GB game shrunk to 10MB) is likely distributing malware or "fake" files, as modern encryption and data density prevent such extreme compression without data loss. Legitimate Compression Methods 3ds games highly compressed