Well it depends on its context. Is it used to describe an increase from current technology or is it a exact measurement.
If you were very technical then you would say exact measurement but instantaneous would then be subjected to measurements way below our understanding of time. So I would assume Dean uses this context to describe an increase in performance from the pervious devices. Consider the amount of time it currently takes for a 3D image to be rendered. In comparison of this time, the DViS would seem instantaneous, would it not?