AW 17 R5 Video Rendering Explanation

Hello My Aw Brothers and Sisters,

I'm a cinematographer and I bought the AW 17 R5 to render 4K vids.  It does a descent job.  I dont have to down res to proxies or any of that.  So I'm pleasantly satisfied with it so far.

I notice looking at my task manager performance when rendering my vids that the machine uses the 630 to encode 3D (seems like the heavier lifting) and the uses the Nvidia 1070 for copying.  Is this the most efficient way to use both GPU's in this machine?  Can this be changed if there is a better and more efficient way?