Hope you have a big SD card tucked away in your Nintendo 3DS. The latest Pokémon games, Sun and Moon, take up quite a bit of space at 3.2GB each. In Nintendo 3DS terms, that translates into 26,176 blocks of memory.
The standard 4GB SD card that comes with the Nintendo 3DS care barely fit that on its own!
Those looking to buy both versions and also keep all of their previous Pokémon games installed are going to have to do quite a bit of fridge cleaning. Maybe that means having an entire SD card dedicated to just Pokémon alone.
Or, if you don’t want to deal with cleaning anything out, the physical cartridges are the best way to get around this frustration. Pokémon Sun and Moon will be released for the Nintendo 3DS on Nov. 18, so that’s plenty of time to make some cuts.
Article source: http://www.technobuffalo.com/2016/10/07/pokemon-sun-moon3-2gb/