In my (limited) experience, straight downloading of the dv from the camera is done in real time, but rendering -- by which I presume you mean converting it (after editing, perhaps) into a different file format for recording onto a vcd, dvd, etc. -- is not done in real time, and can take hours depending on the specification of your PC.
My 600MHz machine with a pretty basic video card takes about 15 minutes for each minute of finished file. Faster PC and better video card will presumably do it faster, by why do you need real time anyway? You only need that when you're playing it back.