AFAIK, he said that setting the depth precision to fastest would be faster..
he also said that there wouldn't be extra noticeable artifacts either (I concur, on my V3 2K AGP overclocked to 183mhz, I don't see any artifacts), though the little help thing that u get when you right click on an option and go to 'what's this?' says that quality goes down.
also, it has been seemingly reported with all those insane V5 + HSR beta driver tests, WITH HSR enabled, depth precision settings DO change the quality..
the speed that they get out of those drivers though, seems to be artificial, because it seems to me that because of the buggy nature of these drivers, and the fact that it shows up some frames aren't rendered at all, means that perhaps the card isn't doing ANYTHING during those frames.
I'll be skeptical till I see WHQL's showing similar improvements without those artifacts.