I wanted to build a large screen for a cinema with all white maps in item frames, but the lag caused by this amount of maps (144) made it unplayable. The lag only appears when looking in the direction of the maps, even when they were behind other blocks.

The framerate dropped from around 80 fps to 20 fps (with shaders on GTX 1080 Ti).

The framerate seems unreasonably bad for this amount of maps even when they are not directly rendered on screen.

tested the same thing in a singleplayer world and the lag was even worse