depends entirely what you save, how you save, whether you want audio and how you format the card. A song can be a midi file, or half the size for the same song a technics sequencer file. You can save space with 10 songs in the sequencer. A technics song may need composers, pads, sounds and effects. Put 20 styles in custom for 20 songs and you save even more space. If someone fills a card with performance saves I could probably re-organise the same information in half the space - equivalent to half the SD card size.