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 Post subject: Apprentice_GM PC silencing project
PostPosted: Thu Sep 14, 2006 1:32 am 
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Joined: Sun Oct 09, 2005 7:12 pm
Posts: 28
Location: Central Coast, NSW, Australia
I first became interested in quieting PC's about a year ago when I bought 2 new A64 3500+ PC's and was subjected to 5 fans going full-bore. Since then I have become somewhat obsessed with the idea of silent computing - (my definition of silence as opposed to 0db is "at least below the ambient room noise at the quietest time" or "inaudible from my usual working position - PC hanging below a desk"). Since then I have been busy with researching quiet components, work and a house reno but recently got around to actually quieting (it's not silent yet) my current rig.

Many thanks to the editors and contributors at SPCR, they are a terrific resource and community :) Any further feedback and advice welcomed - this is definitely a work in progress.

Here is what I bought in October 2005:

Motherboard: Gigabyte GA-K8N Ultra9 system board with Nforce4 Ultra chipset
CPU: AMD Athlon64 3500+ @ 2.2GHz
RAM: 1 GB DDR Kingston RAM
** Updated 1/1/2011 to 2 x 2GB - no new pics **
HDD: (Initially & in pics below) 2 x WD SATA II 250 GB 7,200 rpm in RAID 0
** Updated 1/1/2011 to Corsair 120 GB SSD - no new pics **
DVD-RW: LG GSA-41697B
Graphics: PCI-X WinFast PX6600 GT 128 MB
Monitor: BenQ FP91G 19 inch (1280x1024) TFT LCD
** Updated 1/6/2012 to 42" LCD **
Mouse: LogiTech Wireless Click! Plus Optical
Keyboard: LogiTech Wireless
** Updated 1/1/2011 to Windows 7 64 bit Enterprise w SP1 - no new pics **

After the initial PC assembly and resulting ruckus, I decided to slow the fans down. Not knowing what I was doing, and not having discovered SPCR yet, I soldered a few different resistors to the different fans I had - a 120mm case fan, a 120mm PSU fan, an 80mm front intake fan (for cooling the HDD's) and the whiny GPU fan.

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I experimented by supplying 12V off a battery and listening to free air noise until I was satisfied I had reduced the noise considerably. Generally I found around half the voltage, 6 to 7 volts, was best. I don't have sophisticated measuring stuff, just a multimeter and ears, so I can't say what the noise dropped from, or to. But it was a marked improvement and I never had any problems with overheating - the air coming out of the case was always quite cool and mobo utilities reported low CPU temps. As the mobo had a CPU fan ramp adjustment capability depending on thermal levels I was safe (I'd left the CPU fan alone anyway).

After a few weeks I found SPCR and read hundreds of threads, thousands of posts. Took weeks. I digested some ideas and made some minor mods:

I tried to get cool air directly to the CPU by modd'ing the chassis duct:

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I had always tried to build neat PC's with cable folding and component placement, but was impressed by the cablegami skills on offer at SPCR.

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So that was what I had up until last week.

Then I ordered some silencing gear - Scythe Infinity heatsink which includes a quiet 120mm Scythe fan, Nexus 120mm, 92mm & 80mm fans, Flex noise absorption foam pads, Zalman VGA Cooler ZM80D-HP, Zalman Northbridge flower cooler NBF47 & soft silicone fan mounts.

I spent all night (literally from 10pm until 7am, although I was working on other PC software builds as well) installing the new components, cleaning the PC (my reno has generated a lot of dust, especially very fine concrete dust) and taking photos, testing improvements one by one. So now Grumpy (my PC) looks like this:

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I have gone from 5 fans (CPU, GPU, PSU, 80mm intake, 120mm exhaust) to a passive CPU, passive GPU and just 2 fans - a 120mm PSU fan (still undervolted via inline resistor to ~6V) which doesn't ramp up anyway so it's effectively silent / absent, and a single 120mm Nexus case exhaust fan running at 12 V hardmounted.

The noise level has dropped a lot, I just wish I could measure it. At night, I can just hear it (I live on acreage where it's pretty quiet except for some animal noises) when sitting at my desk. Disappointingly though, the noise quality has gone from a low frequency / wideband woosh, to a kind of thrumming. I have tried 2 x Nexus 120mm and both do the same thing. They look a bit unbalanced, if I spin it by hand I see a bit of movement which is absent on my other fans. I haven't tried all 5 fans I bought but I am not happy with the quality control. It might get better though if I 7V it, everyone else at SPCR rates the Nexus 120mm Real Silent fans so I am hoping that makes a big difference. Otherwise I think I will put the original MEC case 120mm fan back in, or the replacement Scythe 120mm (the original with the Infinity heatsink had 4 broken arms on arrival), or maybe soft-mounting will help. I bought some silicone softmount grommets, but I have to mod the Nexus mounting hole corners to pull them through.

I am really happy with the new noise level. I can hear HDD's much more clearly now, when de-fragging it is the loudest noise for sure.

I couldn't fit the Zalman chipset flower heatsink due to the graphics card - the onboard one is reasonable but I thought taking away some fans I'd need to ramp up the NB cooling. I can't get a temp reading on this from the Gigabyte mobo utility.

Still to come is softmounting the case & PSU fan, ducting the Infinity to the case exhaust fan (my CPU temps are ~30 degrees doing office stuff, hardly seems worth it), ducting the PSU into a separate chamber (also hardly seems worth it given the fan hardly ever ramps up) and softmounting the HDD's. I have an idea for the HDD's using a DIY heatsink, and either elastic suspending them as others have done - but with a heatsink for better cooling - or using silicone mounting blocks which supposedly stop vibration transfer to chassis. Kind of a cheaper and hopefully better solution than Zalman's ZM-2HC2.

Here are my DIY HDD heatsink ideas - anyone recommend for or against a model?
Image

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In theory, practice is the same as theory. In practice, it isn't.


Last edited by Apprentice_GM on Wed Aug 29, 2012 6:05 am, edited 4 times in total.

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 Post subject:
PostPosted: Thu Sep 14, 2006 4:02 am 
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Joined: Mon Nov 24, 2003 10:22 pm
Posts: 106
Location: Uppsala, Sweden
Nice to hear you found SPCR =)

I'd recommend the the last one. There's a reason all heatsinks look like that.. in the two above, I reckon the heat from the part of the heatsink above the HDD but below the top-most part will heat the air in between, which will rise and give unnecessary heat to the top-most part.

But I don't know, in reality maybe it won't make any difference? I'd still go for the bottom one.


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 Post subject:
PostPosted: Thu Sep 14, 2006 4:31 am 
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Friend of SPCR

Joined: Sun Oct 09, 2005 7:12 pm
Posts: 28
Location: Central Coast, NSW, Australia
Thanks for your input ecto - I think if there is a bit of longitudinal airflow (as I intend to place them in a 5.25" bay and draw air through the heatsink gap) it should be fine (link a cpu tower style heatsink).

The bottom one is a bitch to DIY due to the number of folds. The top one is simple, one fold for each piece. I am leaning towards it myself :)

Yeah, SPCR is a great place :)

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In theory, practice is the same as theory. In practice, it isn't.


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 Post subject:
PostPosted: Thu Sep 14, 2006 5:18 am 
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Joined: Mon Nov 24, 2003 10:22 pm
Posts: 106
Location: Uppsala, Sweden
With a little bit of airflow I think it'll be just fine with any of the designs. Because you are thinking about making a HDD heatsink I was too hasty and assumed it was going to be passively cooled.

And, as you say, it's alot easier to make the top one compared to the bottom one if you haven't got the right tools.

Keep us posted with temp info before/after the heatsink. :)


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 Post subject:
PostPosted: Thu Sep 14, 2006 8:33 am 
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Joined: Thu Dec 08, 2005 1:40 pm
Posts: 671
Location: Sweden
#1 should be fine and do the job properly just as #2 and 3.
You might want to drill a couple of holes in the fins (above the HDD) to allowe any natural convection and make sure no air gets trapped but if you have a fan it's unlikely that will happen


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 Post subject:
PostPosted: Wed Sep 20, 2006 9:51 am 
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Joined: Mon Feb 10, 2003 11:19 am
Posts: 291
#1 is as good as any, and certainly the best to fabricate. Keep in mind that thickness and type of material makes a difference, particularly for fins that large. Think of the fin as a pipe for the heat. If you use a small pipe, the heat will have trouble getting to the outermost surfaces. Gut feel says 1mm thickness aluminum will take advantage of the whole fin. Thinner than that and you probably shouldn't bother making them as big.


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 Post subject:
PostPosted: Wed Sep 20, 2006 11:19 am 
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Joined: Mon Mar 27, 2006 8:11 am
Posts: 306
Location: Silicon Valley, California
take away both of your nexus and see if you are still getting noise.

i have found my 7-1 floopy drive generating sh1tload of electric noise.

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