NVD3DUM Eating CPU Cycles

I've been doing a little profiling work on my games engine and have noticed that an inordinate amount of time can be spent inside the NVD3DUM.DLL module, and VTune reports up to 50% of my CPU workload happens inside.  For now I have resigned to accept that this is probably the driver handling the preparation and submission of my graphics data to the GPU but that's just a guess, and trying to find information about this module is pretty tough with almost no information on it.  There also does not appear to be any VS symbol (PDB) files available for it, so I don't know exactly what it's doing when I drill down into it so that's another shroud of mystery to tackle.

Does anyone have any links or information on this module, what it is doing, how it can be optimized and perhaps how to get more symbol style information on it, at least enough to give me a clue what general area I should be optimizing.  If anyone posts something useful, I promise to add it to my daily blog and lavish you with praise for digging out information on what seems to be a black box library that is stealing more than half of my processing cycles!

All I can guess is that NVD3DUM stands for NVIDIA DirectX 3D Unmanaged Driver, but beyond that, it's a mystery module!