I can hear the fan noise if I really listen and the room is quiet. It is an extremely quiet constant background noise. I am not someone who expects a completely silent computer, but this other noise is audible when you are not even near the laptop.
The noise I am talking about is a lot louder / intrusive it kicks on/off extremely fast when you open, close or save something, making me think that think that it is just a loud hard drive. It definitely has a percolating popcorn popping quality to it rather than a constant whirring. I would swear it seems to be coming from the top left part of the keyboard.
Is this a normal iBook sound?