[pHaestus]

Right. So the only real solution to lower fan noise on the radiator and still have acceptable cooling is to oversize the rad more, choose the proper radiator design for low CFM airflow, and then undervolt quiet fans. This is known. I am assuming that a 2x120mm radiator is an absolute must, and a 3x120mm radiator would be preferred. Do you hit the crossover point where water is better than a top end 120mm fan heatsink at 2 or 3x120 rads? Do you hit the point where you cannot physically fit it in the case before this crossover point for performance?

I would also assume the radiator should be muffled by the case as much as possible to let some of the noise be dampened by the case. This probably precludes any hdd cages in the front of the case? Or else top mounted radiators? This will also require some airflow planning or else you'll hurt cooling by using warm case air for the rad intake. No biggie?

But the big thing from a noise standpoint is the pump. You guys must have very different experiences from me, because every pump I've ever used has made SOME noise. None of them have been silent, and almost all of them get progressively louder and "rattlier" (lol making up words) over time. And reservoirs add another noise issue: the gurgling of water to go along with the pump. I have a few pumps I guess are quieter than the average case fan, but none of them are really all that great. Ya I have an old Eheim 1048 too. I am assuming that custom boxes and mounting for dampening are also required along with the proper pump.

And the final consideration is the airflow around the socket area. I REALLY think the lack of surface motherboard cooling is a danger in wced systems. If you're adding a low noise 120mm fan to blow air into that area, then why not just use a low noise 120mm fan on a heatsink?