It’s an updated version of 3Delight. it should be a bit faster, at least (depending on what you compare it with) and should have bug fixes. It wasn’t an ideal way to describe the change, I think, as a lot of people would expect it to mean a new renderer rather than a new version of the existing renderer.
I have run a few tests. A test scene I have been working on that took about 18 min to render in 4.5, renders is 14 min in 4.6.
I also re-render the biggest scene I have have rendered. It seemed to render faster than I remembered. It took 2 hr and 24 min on 4.6. As I remember it was over 3 hours on 4.5.
Memory usage rendering that big scene also appears to be similar, around 14 GB of RAM for DAZ process, 15 GB total system.