The 4.1 is now a 5.1... Cool. Installation of the 3680 CPU was a breeze. I took my time and installed it slowly and carefully. Using assembly methods I have learned in the past such as criss crossing the (not overly) tightening of screws. It runs circles around it's old (and still quick) self. The 1333 ram is now recognized and it's Cinebench scores are doubled at 8700. What a great machine. What are people going to say about the Mac Pro 6.1 ten years after it's release? I doubt that it will be as loved as the Classic is today.