In our noise level tests we switched off all the case fans and replaced the AMD Radeon HD 7950 graphics card with a HD 5550 passive model so were just taking into account the noise generated by the cooler fans themselves.
We measured the noise level with a Digital Noise Level meter at a distance of 1 m from the front of the system.
The noise level generated by the cooler with the fans running at full speed is deafening. We would definitely recommend using the fans' PWM capability.
I bought this today, cant wait to get my hands on it.
These are great coolers, I love my Seidon. they are bit expensive, but good quality.