When I was building my P4 XP rig, I was planning to use the Northwood P4 HT 3.06GHz that I already had, and luckily for me the only s478 cooler I was able to find (Akasa AK-675S) said that the 3.06GHz model was the maximum it supported. The motherboard I got came with a 3.4GHz Prescott, but I...