This image was rendered with NVIDIA's Gelato Pro GPU assisted renderer and was used for display at their Siggraph booth earlier this year. I created an earlier version of this image to test out the abilities of Gelato, then 'upgraded" it to this image for them at their request. The image I submitted to them was at 1920x1200 resolution and it rendered in about 12 minutes! Which is pretty good for an image combining GI, DoF, micropoly displacement etc.