If you notice, case Mfg.'s do not advertise based on their product's ability to perform quietly and take in to account the 'silence' factor. Fans are the components of a system that make noise, not the case. Cases are all silent. Steel cases tend to resemble the sound of a mouse. Aluminum cases, on the other hand, have the propensity to sound like a bad rap song coming at 200 dB from the car behind you at a stop light. So, none of the above.