While I’m not even a beginner with graphics, of the many pages I’ve read about graphic performance many state that a single large texture will be faster than many small textures as there aren’t as many draw calls being made. That’s mainly only with a single mesh or like with your video though.
Quote: col000r
Each material on each mesh causes one draw-call per frame, per light that affects it and per camera that sees it.If I have 1 mesh with 20 seperate textures, only ambient light, one camera, this will also result in 20 draw-calls. If I would combine the 20 textures into one atlas the scene would now only need a single draw-call.
If I have 20 meshes with one texture each, only ambient light, one camera, this will result in 20 draw-calls.
If I would combine all the textures into one big atlas, the scene would still require 20 draw-calls, even though all the objects would now use the same texture.
Since each draw-call requires a bit of time per call, this is probably why your large texture works faster under the hood. Google search with more information.