what if i told you that some of my vue renders take up to 12hours. depends on the objects you have on the scene. for example hair  and eyes take a long time to render. trabparency and water as well. and if the number of polygons present in yr scene is big il will slow down the computer and increase the render time. i use vue 5 infinite and radiosity takes time comparing to global illuminbation but gives best results.
not familiar with the new version of vue and the vray option.