how silent are barebone systems?
 

Suppose you were to compare a pal 8045+papst cooled system (no case fans) with a barebone system.
Is there much difference in noise levels?
Is it doable to run a barebone silently but still cool adequately?

Fan makes noise; or should I say "when the wind blows, the tree sounds".

Air flow is necessay to get the heat out of the chassis, which is generated by HDD, memory, chipsets, VGA, modem, CD drives and CPU.

Unless input=output; meaning no loss at all (currently doable in fission and fussion); it is achievable to have a quiet enough system with sufficient cooling with fan noise below the ambient sound level. You won't notice the fan noise if it is below 35 dBA.;)