Because Ati's owner has less money spend on their R&D is my own take on it. They got the hw, gaming shows their competitive, and looking at raw numbers they should excell in massively parallel tasks like crunching. But like I said, their not backed up with the needed R&D.

But then again, think of it this way, that ppd you will not get running a cpu! Well maybe the one in your sig highly clocked with two linux clients on it, but normally no. So like you already said, it's relative performance about which you talk.