The CPU and GPU aren't components I would have chosen for a silent rig, but nobody offered to give me low-power, high-end computer parts.
It's a fairly standard build: Scythe Ninja, VM-101 on the graphics card, Centurion case. Its only fans are three 120mm units at ~900RPM.
The most innovative part of this build is the PSU cooling solution. I tore the 80mm fan out of the PSU, and ducted a 120mm fan in the 5.25" bays to the PSU. Since the fan is pretty far from the PSU, the duct has to be free of leaks. This is achieved with cardboard and duct tape. The duct has both right and left walls, and the PSU's cables lie outside the duct.My graphics card gives off about 60W, which I think is a lot. At first, I was having trouble with it overheating. It was getting as high as 105°C, then throttling.
You'll notice the fan on the Ninja is 20° off center. The clips that came with the Ninja seem to allow that sort of arrangement. It generates enough airflow across the VGA cooler to keep the GPU below 65°C. It also keeps the northbridge cool. The Northbridge is sandwiched between the VM-101 and the Ninja. It seems to get as hot as 55°C, but it hasn't died yet. The CPU is nice and cool. It stays below 60°C under load and idles around 25°C.
This rig is very quiet. It's about as loud as the very faint hum of my CRT. It's quiet enough for me to sleep in the same room as it, but not quiet enough for someone who didn't love computers to do the same. There's room for improvement.
Room for Improvement
Running the CPU fans at 5V might keep things cool enough even under load; I haven't tried. But my impression is that the PSU fan has to be kept at 7V anyway.
That is, unless I were to drastically mod the PSU. There's enough room inside the PSU for a 120mm fan. I could cut a hole in its bottom wall and attach a 120mm @ 5V blowing in. But in order to feed such a fan with cold air, I'd have to put the PSU outside the case. Either that, or cut a big hole in the top of the case, which would allow cold air and foriegn particles directly into the PSU.
The bottom third of the PSU is empty - presumably to allow the same PSU internals to be used in PSUs with a fan on the bottom.
Fan speeds are static: 7V by using the 5V rail as a ground. I like them static for three reasons. One, if the computer crashes (which might disable CnQ or otherwise increase power consumption), fan speed remains adequate to cool the PC. Two, Speedfan can't monitor my GPU temp or my fan speeds. I presume that's because it's not 100% compatible with the Asus A8S-X. Three: PSU fan speed regulation without PSU temperature monitoring is just asking for trouble. But if I were to get a fan speed controller, I could definately run the fans at 5V at idle.
The hard drives are mounted using the Centurion's default plastic retaining latches, which is good enough for me. I'm from the old school, and I like to hear my hard drive seeks when I'm at the computer. It's like an audible HDD LED.
