Raytraced mode and navigating

@nathanletwory I wish for a faster manipulation of the view when raytraced.
Can you please turn on 4x resolution downsampling as default?
And would it be possible and faster if Cycles waited 0.1 seconds before attempting pass 2? Now it seems like it is always trying to calculate and that it slows down viewport update speed when moving around something.
Anything that would speed up the ability to manipulate objects or moving the camera would be great.