Typical FBX export speed?

[MeHoo]

I realize this is one of those "how long is a piece of string" questions, but I have to wonder if something is wrong.  I've let FBX exports on ~15m face meshes with vertex normals go for hours and seen 0% progress.  OBJ takes a few seconds.

Dual quadcore, 256gb ram, 3x gpus.  Latest Photoscan as of this writing.

I am merely trying to get a mesh with the vertex colors out of photoscan to see if they are even usable for me.

[MeHoo]

UPDATE:  This one did actually finally export, but it showed 0% the entire time then the dialog just disappeared.  Perhaps the progress bar should be more of a functional thing?