Yep I already started using RenderDoc with the plugin and its simply amazing, actually it may have already pointed out the problem in our case which is instanced meshes, to simplify the explanation its somelike like other instances of the 2nd wall are closer to the camera than the 1st wall, although it should be frustum culled need to examine further.
We already use ProfileGPU but its very vague especially for mobile projects its almost empty (just base pass with single item, lighting) so its not much of a help, definitely looking forward for better GPU profiling Epic guys are working on.
I don’t use occlusion culling since it doesn’t work for mobile, precomputed visibility would work but is not feasible for our game level hierarchy. All materials are opaque I mean transparency is killer on mobile anyway and Z-Pass is on auto.
Anyway big thanks, especially for the RenderDoc which will be a huge help to me with UE4 and outside.