Before you read further please understand that this thread is not being created to start an argument about what is overclocking and what is not, that said, here you go: From Croquer Dans La Pomme: "G5 Bi-2.5 GHz currently delivered were initially envisaged to 2.2 GHz. It was thus necessary of the watercooler with the system which one knows to make them hold rate suitably." (A rough translation) Surprisingly, this could make sense, these chips do run pretty damn hot. They idle anywhere from 45C-60C and under load they get up to 70C-85C. That's hot!