Win7 64, GTX 770
Using startup command: --enable-new-depsgraph
Playing animation in viewport while using the Material render view with a Group Instance in the scene , causes fps to significantly drop even when no objects are on any visible layer.
Open file, play animation.
Disable layer 2 (group instance), enable Material shading view, play animation.
Delete empty object from layer 2, then play animation again
Notice animation plays slower in Material view, despite no meshes being rendered nor objects in the layer.
I have a Daz3D character mesh with a quick animation on it..
The frame rate is set to 60fps; the rig is basic so normally, if you only view layer 1, you can play at 60 fps no problem.
If you're in Material shaded view, it also shouldn't be a problem because the rig isn't being rendered.
However, if you have a group instance, containing the dense mesh, inside the current scene, the playback fps will drop.
I also tried adding three subdivision modifiers to the meshes.
Playback is fine while not using new-depsgraph, or not using Material view but if both are enabled and the meshes are instanced in a group in the active scene, the mesh will calculate as though it were visible.