Actually, Aja doesn’t always recommend their card get top billing. See excerpt from their FAQ (last sentence). . .
John
Question: Is KONA 2 PCI-X slot usage in a PowerMac different from Kona HD?
Answer: Yes, on Kona HD we recommended having the RAID controller card on the same PCI bus. For KONA 2, you can install it into either the 133 MHz slot or one of the 100 MHz slots in the PowerMac