Rajahal,
OK thanks for the clarification. I must say that's a bit surprising. A thankyou also to AwesomeD.
The PC-P80 was one of three strategies I was considering for noise abatement but given what you have both said I think I'll have to consider the other two.
My current rig is a 4U, 16-bay Chenbro box - I'm pretty sure that no matter how much noise that a PC-P80 produces it'll be nothing compared to the Chenbro (it has 5x 80mm fans that produce 45dBA each!!!)
So my other two choices are to replace the fans in the Chenbro with something quieter or to go ahead and build a new rig with a different case. I've got a PC-343b and some cages but I haven't unboxed them as yet because although I'm sure I can build a relatively quiet rig with this I'm not sure where I'm actually going to put it due to its' size, hence the reason for considering the PC-P80 in the first instance.