[lee_s]

Eink uses a raster mode, but with (somewhat) tri-state pixels. You can send a 'no change' to any particular pixel. The disadvantage is you still need to scan the entire screen, so it isn't really useful for changing individual pixels, but partial updates are common.

The other difference from a traditional raster display is there is no minimum refresh rate.

Eink controller chips use an addressing model and handle the partial updates for you, so the main processor sees a bare framebuffer.

[ant6n]

Note the link I submitted above, where it says that yes you have to send all rows with every refresh, but for every row you can tell it not to do anything. Presumably that means if you skip all but few rows, you'll get a faster update.