A stupid question

[Jumpem]

How much louder is a case with several (6 to 8) 80mm, 92mm, or 120mm fans compared to a regular case with just a power supply fan?

 

[Zoltarc]

It depends on many things, they are.

1) What CFM they are rated at.
2) Where you mount them.
3) How you mount them (eg using ruber spacers to stop vibrations).

The answer is a hell of alot lounder