That was a 16 hour rendertime with 5 cows running. I should also be a little more precise in my settings; Environment mapping. Global Illumination. Volumetric sunlight enabled Image based Lighting, mapped to skydome and environment, but not mapped to the sky (the brick tile texture made the cloud layers look funky) Final quality setting. The only things I could have twisted higher was going to full Global Radiosity and Broadcast mode, with motion blur and final pass optimization enabled. I won't even =consider= HDRI for animating. Not without a 50 node renderfarm, at least. 16 min per frame is about what it averaged, give or take 5 minutes (the Athlon 64-3000 could chew through almost 2 frames before the 2500+ finished one). I'll have a better idea what is going on when I start the run using the global ambience, but I suspect part of the time was the fact that the image used in the IBL was color, and had quite a few color values in it. This was a torture run; now I have a benchmark to pull back from and find the happy medium....