Ok, first off, I'd suggest you clarify what you're looking for....
Loudness during boot up (why people think that matters I don't know... it's not like you're rebooting 100 times a day...) ???
Loudness while idle?
Loudness while under full load?
And honestly, folks, unless you're working in a sound studio (in which case I question why you need high end high performance graphics card to do audio work) WHY DOES IT MATTER? It's like you're expecting to run a high performance turbo charged V8 engine with the radiator from a Yugo... OF COURSE it's going to be loud under load!
Personally I care more about, how loud is it when I'm NOT loading it up... When I'm just surfing the web and not really doing anything I want it to be quiet. If I can hear it spinning up while I'm doing high performance graphics work or gaming, fine! I'd rather hear the sound and know the fan is running and that there won't be any magic smoke coming out of the case than not hear it at all and having to wonder...
Granted I don't want the machine to sound like a jet engine, but seriously, I don't get why people get so bent out of shape because the fan on the 4870 goes to max during bootup and is loud for the whole 2 seconds before the machine starts running.... It's SILENT after that!