A silent case may seem like a "sales gimmick" to some people, after all how can a case make noise? While it is true that the case itself isn't loud it can help transmit sound. After all it is the fans and other components that actually generate the noise. But the direct noise is only half of the battle, many of the sounds you hear coming from your case can be traced back to all of the moving parts and their affect on the case itself.

http://www.ninjalane.com/reviews/cases/cm-sileo500