Making a noisy computer quiet
Well, I'd had enough of the noise coming from my computer. This is the new/old one that was resurrected to run Linux on.
The first thing that became abundantly clear was that the amount of noise coming from the various fans in the case would not be acceptable if I was to use this computer as a glorified typewriter. The noise was simply too distracting.
Since the definition of "noisy" will vary from person to person, I decided to quantify my results scientifically. To this end I obtained a sound level meter in order to get unbiased results. The unit I got was a cheapy, the Digitech QM-1591 from Jaycar Electronics. It states on the packaging that it is rated to measure 40 to 130 db of noise with a frequency range of 32Hz to 8kHz. This would be more than adequate for my needs.
First, I would need a baseline for comparison. I happened to wake up fairly early in the morning so I took advantage of the quietness of the house and took a reading at 4:30am while everyone else was asleep. The fridge wasn't running and all I could hear was a cricket somewhere in the house looking for his lady friend. I measured 20.5db - really, really quiet.
That was my baseline, now I needed a control group. Rather than firing up all the other computers and measuring their respective volumes (the laptop would have come out at 0db since there are no moving parts when the fan is off) I simply measured a conversation between me and my brother. We were about three feet apart with the meter halfway between us. Our conversation measured at 66db - which is about normal for a conversation. This meant that the meter was working properly and within acceptable tolerances.
So, just how loud is the computer? With the meter in front of the monitor, the computer was spitting out an incredibly annoying 69.5db! Meaning that if we were having the same conversation, we'd have needed to raise our voices to talk to each other! I knew it was loud, but didn't realise just how loud it was.
So what to do? The first thing that had to go was the power supply. The case still had the original one it came with, and it wasn't an expensive case when I bought it. I picked up a Corsair VX-450 which would give out a respectable 450W - more than enough to run this little computer. Actually, comparing the two power supplies it became evident that this particular PSU might have been a bit of overkill:
The only things that the old PSU was connected to were the main loom for the motherboard, the CD drive and the HDD. The fans connected onto their respective sockets on the motherboard itself. The new power supply had enough connections to run a dozen drives and some pretty big video cards. Oh well, the main thing I wanted this particular PSU for was for the 120mm fan mounted underneath it. Bigger fan = lower rpm's to move the same air = less noise.
And it did make a change. After re-building everything the noise dropped to a much better 53.8db. A nice improvement on the previous set-up, but still on the noisy side. The video card does not have a fan, so that left the CPU cooler and the case fan.
I decided to be lazy and change the case fan first. (In the above image you can see the power supply fitted and the spot where the fan used to be on the left.) It too was an original part and the fan had collected a bit of dust over the years. I think it might have been a little chipped as well or something because it sounded like it was off-balance.
Long story short - I picked up a Noctua NF-R8 80mm square fan. It didn't have any fancy lights or even a grill, but it did claim to be very quiet. Having gotten it home, I opened it up and was most impressed by this little fan. It had some blades on the fan that were obviously designed with a bit more thought than "move more air" and comes with a variety of different connection options depending on just how quiet you wanted it to be.
I went for the "most quiet" option (by fitting the Ultra Low Noise Adapter inline on the power lead) but after installing it I found a problem that should have been obvious - the big 120mm fan on the PSU was sucking air up into the PSU and causing the little Noctua fan to back-flow. A quick re-location to the front of the case so that it pushed air across the HDD and it worked beautifully.
I'll add a quick note here that the NF-R8 came with some really nice sound-absorbing rubber mounts along with the normal mounting screws. I tried to use them, but found that they were too difficult to insert. I ended up using the normal plastic mounts instead.
With this change the computer was now registering 49.3db - more acceptable, but alas! The CPU fan was the main offender. It rattled away at full speed and turned out to be the main culprit of the internal noise.
A quick hunt online found a really snazzy-looking CPU cooler from the same company: the NH-C12P cooler. I had really liked the little Noctua fan (I think it's as good as a similar Thermaltake Smart Fan I have had before) so waited with baited breath for the CPU cooler to arrive.
When it did, I realized a minor problem - it was big. I mean BIG! With the first problem being "how the hell to mount the thing"? I opened up the box and had a bit of a play with it.
One thing was immediately apparent: it wasn't going to fit. This computer has the CPU right under the PSU and the side cover does not have any air holes to let air into the case from the side. The next thing that became apparent was that it really wasn't going to fit - at least not without drilling into the motherboard! This cooler is designed to go on motherboards with four holes around the CPU specifically put there in order to mount oversize coolers.
I played with it for about an hour in the forlorn hope of being able to work out a way to mount it; but it was useless. I had this mammoth cooler and no way to mount it. Memo to self - read the specifications first! Specifically the size of things before ordering them...
Deciding to try software fixes (since the hardware option wasn't going to work) I had a hunt around to see if there was a way to slow down the CPU fan in the BIOS or something. Half an hour and two restarts later and the fan was auto-slowing when the CPU wasn't hot.
This final change brought the sound down to a much more manageable level of 45.6db. Not quite as quiet as I had originally hoped, but much quieter than it was before I started.
Having gone through that, I now had a quiet computer and a massive CPU cooler left over. The obvious thing to do now is to build a big media computer to put in the living room. This way I'll be able to put that big cooler to use - but this time, I'll make sure that I have the proper motherboard for it!
Last updated: Sep 2008