My PC tells me the 590 has 7GB internal storage of which 5.53 is used leaving me 1.48. I have the latest LM update NA City Navigator 2020.10 and software V 3.30. When I called Garmin in 2015 and asked how large an SD card to get they told me 30GB and said that when the internal storage was full the map update would partition and install itself on the SD card. My SD card now has just 3GB of music on it in an mp3 folder. I don't have much music on it at all, just enough favorites to keep me happy.