Noise depends more on the components you put in the case than the case itself. Yes, cases can dampen noise, but they cannot get rid of it. Choose good, quality components that are silence optimized, and you should be just fine. For one of Linus' cooling test bench videos, he put the mic right up to the case, and you could barely hear anything, even though it was in a Corsair c70, which is not technically a silence optimized case.