Fixing fan noise and lowering overall computer noise...

December 29, 2008 8:12 PM

Homebrew PC is making a lot of noise — advice on how I should fix this?

My homebrew is making a lot more noise than it usually does.

1. I suspect that it is one or more of the three fans: One fan for the case, one for the power supply, and one for the CPU.

2. In the course of repairing this, I would also like to dampen as much noise as possible — it was making a fair amount of noise before this issue started, and I use this machine as a video jukebox.

I don't have a lot of spare parts, unfortunately, and the nearest parts shop is about a two-hour trip.

Question A. Is there a safe, easy and inexpensive way to figure out where the noise is coming from, without buying one of each part?

(I can't seem to unplug the case and CPU fans without the computer throwing up error messages on boot-up, and I don't know how to disable the power supply fan.)

Question B. Once I replace the bad part, how can I dampen noise coming from the case?

This is a micro-ATX case. If you have a recommendation for a replacement case that is built to reduce noise as much as possible, I'd appreciate your advice there, too.

posted by Blazecock Pileon to computers & internet (17 comments total)

A. I just reach in the box and unplug each of the fans until the noise stops. Its pretty easy to figure out which one is the loud one. Dont worry about errors. Youre just unplugging them for a moment. The fan in the ps cant be turned off. If thats the one thats gone bad then you need to replace the ps.

B. Replace the loud fan and shop around for quiet fans. For instance, Zalman sells silent CPU and GPU fans. Most likely its one of those fans causing the most noise. Quiet case fans are easy to get too.
posted by damn dirty ape at 8:33 PM on December 29, 2008

This site has a whole bunch of guides and reviews -- it's dedicated solely to making your PC quieter.
posted by stavrosthewonderchicken at 8:40 PM on December 29, 2008

Just stick your finger in each fan to slow it down briefly and see if the pitch of the noise changes.
posted by JackFlash at 8:44 PM on December 29, 2008

Just stick your finger in each fan to slow it down briefly and see if the pitch of the noise changes.

All I get is a loud flapping sound. If I try to stop fans, the computer beeps too loudly for me to hear anything else.

This site has a whole bunch of guides and reviews -- it's dedicated solely to making your PC quieter.

Unfortunately, silentpcreview says everything it reviews is quiet, which makes me question whether any of it is actually quiet, or at least makes it difficult to decide what to spend money on. Does anyone have experience with any specific components?
posted by Blazecock Pileon at 8:51 PM on December 29, 2008

If you have to isolate which fan is the culprit without touching them you can use a paper towel or toilet paper tube. Hold to your ear and place the other end directly next to each fan in turn.

nth the Zalman fans. They are great and very quiet.

Another easy thing to do is get a package of assorted rubber washers/gaskets and put them between vibrating components and the case. e.g. remove your power supply, using a glue stick attach small, thin rubber washers to ps over mounting holes and then re-attach. You will be amazed at how much this can help. works for fans, hard drives, optical drives, etc. your case is one big resonator, you need to stop it from vibrating.
posted by ijustwantyourhalf at 9:19 PM on December 29, 2008 [1 favorite has favorites]

SpeedFan is a free Windows program that monitors a lot of hardware sensors like cpu temp, hd temp, etc, but it also lets you tweak the fan speeds in software. You can set the fans to adjust their speed according to the various sensors (like many laptops and some desktops do already) but you can also just fidget with the speeds to see what fans are making what noises, without opening the case. Of course this depends greatly on your motherboard, though in my experience SpeedFan has support for a huge range of MBs.

You can do this in Linux as well, but the support is spottier. Loading various kernel modules will create files in /sys or /proc or somewhere like that (I'm not on that computer at the moment). Figure out which one controls the fan (it will be named something like fan1_pwm) and write a number between 0 and 255 to that file to set the speed. Controlling the fans on Linux will take quite a bit more effort and googling, and is less likely to work at all. If you have the option to use SpeedFan, I'd try that first.
posted by scope the lobe at 10:15 PM on December 29, 2008

If I try to stop fans, the computer beeps too loudly for me to hear anything else.

That's probably a BIOS setting that is alerting you to a "malfunctioning" fan. See if you can find something on the bios screen when you start up to disable this.

And Zalman fans are great. I've got four of them running full blast to cool the electronics in my in my media cabinet. When the room is quiet I can't hear a thing. If you look at the specifications on a site like NewEgg it has noise level information for virtually every fan it lists.
posted by Ookseer at 10:27 PM on December 29, 2008

Check your BIOS to see if there's a way to turn off the alarms for missing fans, especially the case fan which can be safely turned off for a while.

Try unplugging the hard drive too, just to rule it out.

When it comes to replacement parts, you need to give SilentPCReview a chance, especially its forums. This question is the raison d'etre of that site and they're very knowledgeable.

I don't know about micro ATX cases, but Antec makes some good quiet cases generally. Corsair's power supplies are excellent. For example, the Corsair HX450W.
posted by Yogurt at 10:29 PM on December 29, 2008

Also, you may be interested in the choices made in a quiet mini-tower designed by SilentPCReview -- they like the Modu82 PSUs now it seems.
posted by Yogurt at 10:37 PM on December 29, 2008

All the fans -- with the possible exception of a video card fan -- can be safely turned off for "a while". Intel CPUs have always had thermal protection, so running them without a fan will simply cause the system to lock, without doing any damage. AMD CPUs have had issues in the past, but I think any AMD CPU of the 64-bit era should be as robust to overheating as Intel CPUs have always been. Even with an Athlon XP era chip, if a reasonably large heatsink is properly mounted, you have several minutes before damage can happen.

I'm pretty surprised your motherboard complains so quickly about the fans being slowed/stopped. I think Yogurt is right, you can probably turn those stupid alarms off.

Consider padding the fans +12V line with a small resistance, or moving the fans -ve wire to 3.3V or 5V -- both measures reduce voltage to the fan, reducing rotation speed, and making the fan quieter. Of course they also move less air!

It isn't that hard, or that dangerous, to replace the fan inside a power supply. Just cut the wires and splice in a new fan -- make sure to use a couple of layers of electrical tape or heat shrink, and make sure to route the wires back where they were and away from any primary side electronics. I mean, do the obvious, unplug the thing. You could also discharge the primary side bulk caps, but in most power supplies they will discharge themselves quite quickly, and there is really no reason for you to be getting near primary side electronics anyway.. all you have to do is find the fan wires, which won't be anywhere near the primary side parts.

I've been able to silence a very loud hard drive by mounting it in a small closed cardboard box. The box had a fan cut into one end, and a hole for cables in the other. That created enough air flow, while keeping enough noise boxed in, that it was quite effective, if ugly. Silencing a whole PC is harder.
posted by Chuckles at 11:32 PM on December 29, 2008

Unfortunately, silentpcreview says everything it reviews is quiet

Wouldn't that be precisely the point of such a site?
posted by stavrosthewonderchicken at 4:08 AM on December 30, 2008

Stock intel fan is usually high pitched. Passive cooled cpu heatsink might be the go. Scythe make them along with quite quiet fans. I have the ninja copper - it is great.
posted by dabcad at 4:14 AM on December 30, 2008

Just don't do what I did--seriously--which is to unplug the cpu fan to see if that was the cause of the noise, be called away for a spell, then return and start using the computer, only to wonder what that acrid smell was.

RIP, Athlon 1600.
posted by alexei at 4:19 AM on December 30, 2008

Hmm... does it sound like your fridge compressor motor? Then it's the hard drive bearings going. (High pitched type sound)
Only fix for that is new hard drive. It could last a while before kicking the bucket, it could die tomorrow.

If it's fans, then do as others indicate, shove something in there. If you're worried about the beeping, hold down the 'reset' button, it'll keep the bios from loading, but will power everything (it won't hurt anything to keep it held down). Then poke at things to hear which is bad.

Also, you can replace a powersupply fan, just let the caps inside discharge, and don't touch them! (Most have a discharge resistor, you can hear them go a few seconds after the power is off). These caps can possibly kill you if you pull a stupid, so if you're not comfortable, get a new powersupply.
(Then unscrew the little screws, and find a fan of similar size. I've just run the wire through the grill (you can remove the molex connectors from the plastic plugs with a teeny screwdriver)

Are you sure there isn't a fan on the videocard? Because they are always the first to break on older video cards, they suck.
posted by defcom1 at 5:20 AM on December 30, 2008

Yeah, first and foremost check whether it's your hard-drive. A suddenly noisy hard-drive is probably very very sick. If you care about any of the data on it, you'll soon be worrying about more than a bit of noise.

If you really care about silence, then don't bother with quiet fans. Look into motherboards / processors / power supplies that don't have ANY fans.
posted by mr. strange at 6:01 AM on December 30, 2008

Just stick your finger in each fan to slow it down briefly and see if the pitch of the noise changes.

I think that I've broken single-bearing fans doing this. That, or I'm unlucky.
posted by a robot made out of meat at 6:26 AM on December 30, 2008

Wouldn't that be precisely the point of such a site?

A good analogy would be reading a Michelin Guide and all the restaurants have been given three stars. It makes it hard to differentiate between the reviews, not to mention that the reviews are all subjective "it sounds quiet" as opposed to "it makes x dB of noise at y ft or m from your ear". It's not a very useful site, IMO.
posted by Blazecock Pileon at 11:54 PM on December 30, 2008