According to the excellent ps_mem memory utility, ncmpc uses about 1.3MB of RAM. Even taking into account mpd consuming around 19.2 MB of RAM, ncmpc offers an extremely light way of listening to your music collection.
As the chart below demonstrates, ncmpc is, in fact, the lightest music player I’ve covered. It’s true almost all the others are graphical software, and so drag in widget libraries like Qt and GTK, or even more weighty web-technologies. But if you want a lean way of listening to your music collection, there’s plenty of choice.
The chart above doesn’t list a few heavyweight music players. For clarity, I’ve listed the biggest 3 RAM hogs in the next chart. Even though MellowPlayer consumes a ridiculous amount of RAM, it’s one of my favorites.