...get active fan control for all fans and let Nexus exhaust fans spin under 200 rpm most of the time. I second Rusty and MikeC.
I have active fan control throguh uGuru, but it's certrainly not that radical. 200 rpm is virually zero airflow. At the very least, my mobo needs the air.
That won't be very quiet, with 5-7 V through rads. The air solution will be quieter than that. To beat a well designed air alternative you'll need better rads with bigger cooling area and extremely undervolted top notch fans. I use 2 x 4412's @ 3.5 V (unless gaming or such) on my rads and they alone make more noise than my whole air cooled A64 machine does when I sit here internetting. Have you considered using large passive radiator(s)? If you succeed with truly isolating the pump it could deliver that Holy Grail quiet for sure.
Only one fan will directly suck
air through a radiator. Nothing will be force-feeding it. The whole concept is to let negative case pressure do the work, especially in the passive rad at the front of the case. The plan is to have only the two rear exhaust fans (rear and top) running at 5v, the rear pulling air through a radiator, the "blowhole" pulling air over the motherboard components, both pulling cool air from the front over a passive radiator. Everything
will be soft mounted. Fan noise should be, minimally, far less than standard P180 operation, idealy, virtually silent.
What better internal
rads would you suggest? I am also considering Thermochill's 120.1; have you a recommendation on that?
I am planning on running 2x 5v Yate Loon 120mm, what's better/quieter than that?
Passive is out, unfortunately, due to space and $ constraints. Although nice, those impressive Knovect-O-Matics are awefully pricey.
Single radiator not as effective as 2x or 3x units (but quieter, and I can always add another later)
Where does this come from? This debate about more or fewer fans should be over by now.
Where did I mention the number of fans mounted to the radiators? I was referring to the size of the radiator (i.e. a radiator with mounting points for 1x 120mm or 2-3x 120mm fans), not the amount of fans I'd be running on it, a point aluded to earlier in your response ("...better rads with bigger cooling area..."). Again, any radiator must be mounted in-case due to space constraints.
I'd say go air or get a cut-no-corners superbly ass-kicking water system. You'll likely regret opting for some half-assed w/c, thus ending up with the worst of two worlds.
I believe, naively perhaps, that the above spec, perhaps with additional tweaks, accomplishes both extreme quiet and superior (to air) performance. With 2x 120mm radiators, a high performance CPU, GPU and Chipset block I expect better system temps all around, not necessarily for any one component. In other words, my CPU may gain a degree or two (going dual core, I expect it anyway), but I should see significant temp drops for my NF4 northbridge, GPU and case as less heated air is spread around. Is this flawed thinking?
Currently I get very good temps on my CPU (26-44c w/ SI-120 on an A64 3200+ @2.4 GHz), marginal temps with my passive Q-OTES cooler (37-47c), and fairly good temps for my VGA (Leadtek 6800GT w/ NV Silencer 5 Rev. 3 51-71c). Am I mistaken that my VGA temps, at least, will drop significantly?
Remember, I'm upgrading to a newer (hotter) card at the same time, something in the 7800GTX/x1800xt range.
Maybe I'll start another thread...