Shader nodes viewport performance

Not sure if this has been asked yet (didn’t find anything related in the topics), but is there some information on why working with shader nodes is heaps faster in small scenes -

as opposed to bigger scenes? -

If a material is not connected to a heavy object shouldn’t it be just as snappy as in a simple scene with just a cube? I mean even moving or creating nodes or adjusting sliders becomes a pain as soon as a scene is getting heavier, no matter if they’re actually connected to the material output.