Just want to add, that my radeon hd4570 is also getting to the point, where games are really playable. Even dota 2, which is based on relatively new technologies is getting closer to what it feels like on windows. It still has some graphics artefacts, fps is around 20-30 in average, but the game wasn't playable at all before.
This benchmark is about the fact that the R600g driver has caught up with Catalyst.
More modern graphic cards use the RadeonSI driver (that one, although it is making progress, is currently not at the same level as Catalyst).
Michael explained it in the first paragraph of the article, actually.