> I have an original 500MHz > unit, have never heard the fan kick in, and it's running an average of 12-15 > hours per day. Mostly on a desktop but in the evenings it's occasionally on > my lap or sometimes sitting on a cushioned foot rest. My iBook is an 800MHz one, I've been using it extensively since last december and the fan has been activated just three or four times in all, producing an audible noise, but with different pitches in different times (I presume the fan's speed is proportional to the heat of the unit). Until last december, anyway, I had a 600MHz iBook, and if I remember well, when I disassembled it to upgrade its hard drive, I didn't notice any fan. Roberto Giannotta Trieste, Italy