Marmoset loads in a fraction of a second, UE4 takes 15 seconds

Why does it take unreal engine 15 seconds to reimport a file after a change in zbrush when marmoset loads the same OBJ in a fraction of a second? I have tried saving quads and tris, with and without UVs. Seems to me the import functions must have been written in very inefficient code, is there any way to fix this?

I’d like to get to the bottom of this, someone please…

unreal is an entire game engine with a history of accretion like two decades or more? Marmoset is much lighter, simpler program and it’s like, five years old?

That’s all i can say, but it seems logical to expect a software that is orders of magnitude more complex to be slower in general.

Can someone who is familiar with the file import and asset file creation pipeline please give a clear answer if this delay of sometimes 20 seconds is intrinsic to how the engine is built or if there’s a C++ code somewhere that can be upgraded to newer and more efficient loading routines?