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First attempt at PC silencing

Posted: Tue Sep 11, 2007 6:35 am
by djkest
So about 6 months ago, I pieced a system together for my wife which (I thought) would be quiet and efficient, powerful and economical. Well at least, powerful for what she would be doing. I used a lot of hand-me down parts Here is the relevant info... [[[SCROLL DOWN FOR PICS]]]

Athlon 64 3700+ socket 939 (retail box cooler)
Gigabyte nForce 4 SLI mobo
1 GB Corsair PC3200 DDR (matched pair)
WD 100GB 7200 rpm / 8mb cache
Pioneer slot-load dvd-rom
Onboard sound/lan
MSI 7100GS / 128 MB DDR2 / fanless
Coolermaster Centurion case
Rosewill 350W PS

I thought that by getting a fanless video card and sticking with the stock CPU cooler, I'd have a quiet PC! wow, how wrong I was. Well yeah, it's quieter than my gaming rig, which sounds like a dustbuster with a low battery. But it is NOT that quiet. There is a high-pitched, metallic, unearthly sound that I couldn't identify. Not ear-pleasing.

So using the method as described on the SPCR forums, I started testing things. First I stopped the big 120mm coolermaster fan on the rear panel. Nope, I could barely hear a difference at all. (I think this fan is moderated by the bios) Next the CPU fan. This was a little scary cause I had a difficult time getting the fan started again and I could just picture "letting the smoke out". I did notice a noise reduction, but not much.

Next I stuck a mechanical extendable rubber eraser in the 80mm fan mounted in the rosewill PS. I was thinking this was in for sure. No, the rosewill is actually pretty moderate (ie didn't notice it). I found a hidden front 80mm case fan... stopped that one. Nope, that hardly made a difference.

So here I am, staring at my motherboard, trying to figure out if somehow this electric whine was coming from my fanless video card. Maybe electrons were bouncing around or something.

I carefully examined the computer from every angle. Finally, I grabbed the hard drive to damp it a little. Immediately I noticed the very slightest change in the high-frequency hum. I shut the computer off, disconnected the IDE cable, and removed the HD from the tool-less cage. I grabbed some large bubble wrap, and made a 2" thick cushion. I set the hard drive on top of the cushion inside of my 5.25" drive bay, reconnected the ide controller, and fired it up. Yes! the annoying noise was very much damped....

...and replaced by fan whine. Oh man, this is gonna get interesting. So I did the fan check again and wouldn't you know, that "stock" CPU cooler is making a huge amount of noise. Okay.

So next step, make a permanent solution for that noisy hard drive, and order a Zalman AlCu 7000 for that computer....

also noticed: the case sides are very flimsy, and most likely that front case fan will be the next weakest link, since it doesn't have any speed reduction on it. And yes i realized my current "mount" for the HD lacks a good ground, so I'll be reversing it.

oh crap, I think I got the bug.

Posted: Tue Sep 11, 2007 7:12 am
by protellect
hahaha. Thats exactly how you do it.

You make one thing quiet, then listen again.

First it was the stock CPU cooler on full bore because it sucked on my 5600.
Then it was first the crappy antec 120MM case fans.
After I replaced those, then I could hear the video card fan while.
Now I can hear hard drive noise :(

It never ends!

Posted: Tue Sep 11, 2007 7:16 am
by djkest
I wonder if my hard drive being that loud is a sign that it is going to die?

Posted: Tue Sep 11, 2007 7:21 am
by protellect
well, there are different kinds of loud..... head seeks are normal.... if its scratchy or something, it might be something to worry about!

Posted: Mon Sep 17, 2007 6:58 pm
by djkest
Okay, so I tore my wife's computer apart, replaced most of the fans, and suspended the hard drive. This computer was built kind of hastily because I actually built 2 computers in one day, and I had a number of things come up that took a lot of time. I went back to try and give it the Silent PC touch.

I purchased an Arctic Cooling Freezer Pro, 120mm and 80mm Arctic Cooling case fans, and some arctic silver 5. I also bought some black zip-ties, black square zip-tie anchors, 1/4" nylon cable clamps (white), and 6' of black elastic "rip cord".

Here's the before picture. Cables messed up a little more than usual.

Here's the thermal 'cement' that came on the retail box cooler. It had hardened to the point that when I removed the CPU HSF it also pulled the chip right out of the 939 socket while clamped!

Here's the after picture with the new HSF and 120mm fan showing, plus some improved cable management.

An angle shot showing the Arctic Cooling Freezer Pro and the 120mm exhaust fan working together for a nice breeze.

Here's the nylon cable clips screwed into the hard drive with 1/4" elastic 'rip cord' loops.

Hard drive suspended in 5.25" bay, with some mobo-box foam in front for protection and some minor sound damping.

End result was about a 5 degree C reduction in idle CPU temp (around 30 C at idle) and reduced noise. Unfortunately having a coolermaster centurion "swiss cheese" case, I can still hear the hard drive pretty well, and the 92mm fan on the CPU heatsink is audible. The 80mm fan up front was reigned in with a Zalman Fanmate 1, otherwise it would have been much too loud. The 120mm fan (in the rear) is very quiet at stock voltage. This is not a silent PC, but it is quiet to be sure.

To coolermaster's credit, the stock case fans were surprisingly efficient and quiet, I probably could have left the stock front fan alone.

Posted: Mon Sep 17, 2007 8:36 pm
by djkest
Next up for this case (in a month or so) is a treatment of the sides, top, and front with some butyl-rubber matting and closed cell foam mat over that. The side panels of the centurion case are very flimsy. Might have to hack into that rosewill and change out the 80mm fan, but so far it's not the noisiest component.

Any ideas to cut down the noise of the 92mm cpu fan? I have it on motherboard control, but maybe I could further reduce the voltage?