Yet another “silent” computer project

There are probably thousands of computer case related stories out there and here’s another one, because I feel like writing and nothing better worth of reporting came to my mind.

My previous computer (which I still have on my table, on the other side of the monitor :) ), was loud as hell. It was put together in the era of computing (early years of this millennium) when only number crushing power was important and noise levels could be insanely high. The main noise sources were the processor fan (the processor is an originally 1.7 GHz Athlon overclocked to 1.9 GHz) and the cheap power source. I still use that computer to burn my CDs and DVDs, because I have my… Oh yes, I haven’t mentioned about that either: I made an accounting program and I sell it: So I have my tools and sources to make those accounting program CDs on that computer. I also use it as a file backup device (some of my old IDE drives are on that computer). And If I’ll ever do some network programming, I need it for that, too.

Like so many others I got fed up with the WWWWWWWOOOOSHHHH. So the next thing I wanted was a completely silent computer. Bought expensive parts. The mother board (Asus M2N-SLI Deluxe) and graphics card (cheap Geforce 6200 card) are passively cooled. A 500W power source (Antec Phantom) is passively cooled when it’s cool enough (the fan wakes up sometimes, but I’ve got it on the lowest temperature setting). I also bought a generously sized copper processor cooler (SilverStone) with three heat pipes. The manufacturer stated that it could be also used as passive cooler. The processor is AMD 64bit X2 (double core).

But when the parts arrived I noticed that I had bough a cooler which is not compatible with the processor slot of my mother board. Damn. I had to make an adapter. But there was no way I could have the cooler in it’s most favourable orientation for passive cooling, which is so that the air could travel vertically through the slots between the cooling fins. Well, maybe I could have, but it would have been hard. I thought that there’s no guarantee anyway whether the cooling could be completely passive, so it wasn’t worth the trouble. Besides the cooler would have been too close to the power source. So, I pointed the fins towards the back wall of the case. This way I could put a case fan to cool the processor if the passive cooling wouldn’t work.

Here are the adapters:

The adapters

They are the aluminium parts between the motherboard and cooler. The picture should be self-explanatory.

Ok. I was ready to measure the temperatures. First, just to make sure, the processor wouldn’t cook, I pointed a table fan towards the cooler. Then I installed the operating system (Windows Server 2003). I had a bit of trouble finding a suitable software to do temperature measuments. Motherboard Monitor didn’t work on Windows Server 2003, but Speedfan did. I downloaded CPU Burn-in to stress test the CPU. I ran two of those to get full 100% of the both processor cores. But things didn’t work out. The temperatures went too high. I reached 70C when I wasn’t paying attention at some point! Luckily the processor didn’t suffer. So I needed a fan. I searched the web and ordered Noctua’s 120 mm NF-S12-1200. This is as quiet as they come.

I dry tested the fan without attaching it to the case, but instead to the processor cooler (some tape and a paper clip was needed). Much of the air went by the cooler, because the fan is huge. I measured the temperatures and the result was: 56-59C, the mean being about 58 degrees Celsius. Still quite high.

Then I mounted the fan to the back wall of the case:

 The fan at the back

Perfect fit :) I cut a fan size hole in the back. I didn’t settle for drilling a few small holes for air intake, because I didn’t want anything to block the air or cause turbulence (and noise) near the fan blades. I have to be a little bit carefull when I’m doing something behind the computer in order not to stick anything to the fan, but you don’t really have do something behind the machine so often, so it’s not a problem.

Then I made guides to channel air to the cooler as effectively as possible:

Air guides

Air guides from beneath

Some sheet metal, rivets and tape was needed for this stage. I measured the temperatures again: 52-54C, the mean 53C. This was with the fan at 70% speed of the maximum which is 1200 RPM and both processor cores at full 100%, of course. At this speed the fan is almost completely silent even when the side panel of the case is open. Actually the side panels have been open for about two months now. I never finish up anything :(

Problems: the hiss of the hard drive is now bothering me. Also the fan of the power source wakes up sometimes. I’ve decided that I need sound insulation on the walls of the case. That’s up in the programme next.


UPDATE 19.03.2007:

 I finally finished the computer. I bought some sound insulation material from a hardware store and insulated the side walls and bottom of the case with it. When I closed up the case (up till now the side walls had been open), the temperature of the processor rose. I had to put the fan to 100% speed which of course is a big louder. However, thanks to the sound insulation the overall noise is a bit lower. It would be sweet though if I could still keep the fan at 70%… It’s a pity that the motherboard doesn’t have automatic speed adjustment for the fan. I’ve already been looking at water cooling systems. Oh, dear… when is it going to end?


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