I have an i7 3.2ghz and its all cooled by 1 fan all in a micro atx chassis and you can hardly hear it even with the cover off.
CPU temp stays around 40degC most of the time.
It’s the dual GPU cards that’s making the racket. But considering they have the computing power of a super computer, the noise is worth it for some.
I have an i7 notebook with discrete Nvidia graphics. Nothing compared to the game rigs but astounding compared to my old dual core integrated graphics notebook and makes no noise.
Currently, I using it as a DVR running in the background.