74 thoughts on “CPU Fan”

1. I had a similar problem and it ended up being a cable that was touching the blades after I put the chassis back together. Try turning it on with out the lid and see if you can isolate the noise.

   1. It’s open. Nothing is touching it.

      There’s a ticking noise with a frequency of about 2 Hz. I wonder if its resonating with something, but there aren’t any other moving parts.

2. I’m currently having similar problems with an antiquated case I’ve had to reuse (my motherboard’s front panel connectors turned out to be in an awkward corner for the nice one I’d set aside). It had me worried about failing fans too for a while, but the noise seems to be coming from the drive bay blanking plates on the front. A gentle tap shuts them up them for a bit, although I should probably get round to a more permanent fix.

3. Well it could be anything really. The CPU fan, the PSU fan, the motherboard chipset fan, the GPU fan, the hard disk, the DVD-ROM drive, etc.

   Try running cpuburn to see if the noise gets worse with load or not. Disconnect all the devices you don’t need, check if the device lights blink when the noise happens or not, etc.

   1. It’s not the CPU fan, it’s not the PSU fan. Those are the only fans I have as far as I know. CD/ROM disconnected, only drive with power in the box is an SSD.

      1. Could be a loose component, then.

         I had a case fan once that made a horrible heterodyning whine. I solved it with a silicone gasket. That doesn’t sound like your problem, but a ticking does sound more like something not screwed down tight, or just not tight.

         The only way to really diagnose that is to pretty much touch everything until the noise stops.

         1. I’ve spent too much of my day doing just that. No joy.

            1. If you have a piece of dowel rod, you can use it by pressing it to your temple, and touching the other end to various places inside the unit to try and isolate the source. Bone conduction makes for a nice stethoscope.

4. Does the tick have a plastic or metallic sound to it? That is something getting a direct hit from a fan. Plastic is a housing, metal is a screw (usually). Does it sound like “whick?” That is a cable getting tugged by a fan blade, maybe between heat-sink fins on the underside of the fan. It could be an electrical component shorting across something. Finally, it could also be radio interference bleeding into the piezoelectric speaker on the motherboard (the one used for POST sounds).

   1. It really doesn’t sound like any of those things…

      It does sound like a resonance of something with something else.

5. Does it by any chance have a fan for the graphics processor?

   Also disconnect the internal speaker to make sure it’s not some bizarre daemon chirping.

   Perhaps try putting a spot of silicone caulk on anything that can possible move.

   1. Does it by any chance have a fan for the graphics processor?

      Not that I can see.

      Also disconnect the internal speaker to make sure it’s not some bizarre daemon chirping.

      That is definitely not the problem. It’s mechanical.

      Perhaps try putting a spot of silicone caulk on anything that can possible move.

      I’ve been pushing on everything that could possible move, with zero results.

6. http://www.harborfreight.com/mechanics-stethoscope-69913.html

   A mechanic’s stethoscope with a metal contact probe. Three bucks currently, so what’s to lose?

   1. I might try that. There’s one a couple miles away.

      1. Just beware – Bring enough cash for what you came for, no more, then get someone at the store to take you straight to where it is. Do NOT wander around letting all the bargain tools whisper to you about the neat projects you could do with them if you just spent a few bucks more! Harbor Freight can be a dangerous place for tool-users…

         1. It can, but they also sell a lot of cheap junk.

            1. Their stuff covers a range of quality. Much of it is as good as you’d get at Home Depot or Ace for two or three times the price. Some of it, yeah, not so much. You have to know what you’re looking at. (Or check the online reviews – you can often get a pretty good handle on whether something will get the job done for you.)

               And in some cases, I’ve found that a cheap tool that’ll last only one job is all I need anyway.

               That said, I’ve had one of their mechanic’s stethoscopes for years, and it works OK.

            2. Yes, it probably will for this job. I’m tracking down a computer noise, not listening for tuberculosis.

            3. Hah. They were having a three-day parking-lot sale. I found one immediately in a $3 bin. And got some epoxy for a buck. Also scored a new bed for the cat for a ten spot.

            4. Yeah, but sometimes you only need cheap tools – But their canvas tool bags are a killer deal! The same ones West Marine sells for 1/4 the price.

            5. Chortle. You went to buy a $3 tool, and got away for only $14!

               I’ve done worse there… Harbor Freight is insidious.

            6. Well, four bucks for a tool, and ten for a cat bed. She seems to like it.

               I guess you could call it a tool for adjusting cat satisfaction.

7. Rand, I’ve had similar case-noise issues a couple of times.

   Once, it was the motherboard mount; the motherboard was vibrating against one of its mounts due to a loose screw.

   Another time, it was wiring behind the motherboard.

   And a third time, I poked around for an hour before I turned off the system and noticed the sound didn’t stop. It was a fan: the ceiling fan.

   1. Ooof!

      I was chasing a very high pitched whine in a friends PC one day, until he pointed out that the noise was coming from another friends hearing aids.

   2. It’s definitely the computer. It’s definitely not anything on the mother board. I can find nothing to put pressure on in the machine to get it to stop. It’s driving me nuts. It seems like if it was a mounting issue, pressing against the loose area would fix it, but can’t find anything.

8. Try re-seating the power cord (PC side). Make sure it is all the way in. If it affects the noise in any way, try replacing it. Check the cord to make sure it is not warm or hot to the touch. It should never be.

   1. The case power supply isn’t even plugged in. I’m running it off a different one outside the case. And that one is silent, according to the stethoscope.

   2. I’m getting to the point that I want to call in James Randi. I think I have a h’ant.

      1. BTW, this now reminds me of something that happened recently to my son’s computer: his power supply was about 7 years old, and the computer stopped booting. Lights came on, fans started spinning, etc., but nothing else happened. I noticed the PSU had started making a rapid ticking noise, so I replaced it and the machine started working again.

         Now that’s probably not specifically what’s wrong, but it can be surprising what *can* cause weird noises.

         You said you’ve tried stopping all the fans with a finger on the hub, right, to verify none of them are mildly unbalanced?

         1. I’ve briefly stopped the CPU fan. That’s the only one to stop. It had no effect.

            1. How did you do that? Did you obstruct it physically or did you unplug it?

            2. I put my finger on it for a second or so.

            3. And no case fan correct?

            4. try unplugging it.

            5. I’m afraid to do that; I might not get it plugged back in quickly enough. It’s not a very accessible location. How long do you think I’d have before the heat sink overheats?

            6. And of course the ultimate stupid question. The noise goes away when you power off the system, correct?

            7. Yup.

            8. Still would like to know if the sound goes away with the fan unplugged. If not, then might be time to look elsewhere.
               As was mentioned before you could remount the motherboard using nylon spacers in place of metal ones, or foam backing, etc. To isolate whatever is causing it. Or you can spend some money on a new case or motherboard. Good luck!

            9. I’ll try it next time I reboot. In the middle of stuff right now.

            10. OK, unplugged the fan. Sound persists unabated.

            11. You should have maybe as much as 5-10 seconds; more if the computer’s relatively idle, like still in the BIOS. An Intel will shut itself down before suffering damage; an AMD _should_ but I don’t know for an absolute fact it will.

            12. I did unplug it without booting. It makes no difference. Something other than CPU fan is making the noise.

            13. I’m reminded of the line from “House”. The master diagnostician. “Everybody Lies”… 😉

         2. When you power off just the ATX case right?

            1. Before unplugging the fan reboot your system into its BIOS only. (F12, ESC whatever). That will keep the CPU idle enough you won’t have to worry about the fan being off. Typically there is plenty of overhead when the heat sink is on. There is plenty of thermal mass there to keep your chip from overheating (WHEN IDLE) with the fan off. So I wouldn’t worry as long as its in the BIOS only. If you’re still the paranoid type, you can use a regular desk fan pointed at it for the short time it will take to see if the noise goes away. Sometimes fans can wear out the plastic bushings that anchor the plastic blades to the metal motor shaft. Usually using a finger will work but if the joint is loose enough the fan shaft can turn inside the fan blade hub. If its a fan bearing issue, the ticking would then continue. If you have a utility that can vary the fan speed that should effect the ticking as well. After hearing the recording it definitely sounds fan related to me. Unless you have some form of removable media in this box. The old, old ZIP drives would sometimes fail during disk insertion or removal with a continuous 3Hz clicking sound. But that doesn’t sound to be the issue here.

            2. I’ve changed the fan, with no joy.

            3. Well this has me intrigued. Without seeing it, it’s hard to know offhand your setup. It’s kinda like a game of 20 questions. Assumptions here are fatal. You say you have no other fans in the box other than the CPU fan. So I guess we have to rule out fan noise. You said you were powering the motherboard with an external PS. Is the case PS powered down when you are doing this? If not try that. You said your CD/DVD drive was disconnected. Some ATX PS’s have overvoltage cutouts that cycle. If the CD/DVD drive is disconnected there may be certain DC outputs (like 5V) w/o loads that would trigger & cycle the PS’s overvoltage switch which in your case might be a mechanical relay. So another experiment would be to hook the case PS back up and make sure you have a least ONE load on each of your PS’s outputs. But if you truly only had the external PS powered on, the noise would have been coming from it, not inside the box.

            4. See my update. I was wrong about there being no other fans in the case. It was hiding from me.

9. Rand,

   Most of the MBs I’ve used have had fans other than the CPU fan. Same with the graphics cards. I also usually install a case fan in front, but some cases have them built in.

   Do you run anything like Speedfan (a great, and free, program that monitors and manages temp and fans)? Mine gives me a CPU temp on the taskbar, and, if I click on that, I get a window that includes a list of SOME of my fans. (every fan that reports RPM, such as the PSU, CPU, and rear fan) as well as two that don’t; GPU fan and Aux fan. (I tend to put in a lot of fans; I live at high altitude so need more airflow to get the same cooling). I’m just guessing that, maybe, there’s a fan you haven’t spotted yet.

   As a distantly related aside, when I was in college I had a computer start acting very weird; crashes, case noises, fan clatter, etc. I opened the case, and found the problem; it was a non-Microsoft-compatible mouse. The two black, beady eyes looking back at me from inside the case where proof positive (it had built a nest in there!).

   1. The case has no fans other than the CPU fan (and the PSU fan, if it was in the case). It’s the case itself that seems to be rattling, but I can’t figure out what it’s rattling against.

      1. If it’s the case itself, it could be a loose motherboard screw/standoff, as someone suggested. Could also be a blanking port cover, a drive bay cover out front, or a loose drive cage.

         It’s not impossible that it’s the side panel or a dust cover for a (not-installed in your case) case fan.

10. How this post ends:

    No doubt I now grew very pale; –but I talked more fluently, and with a heightened voice. Yet the sound increased –and what could I do? It was a low, dull, quick sound –much such a sound as a watch makes when enveloped in cotton. I gasped for breath –and yet the officers heard it not. I talked more quickly –more vehemently; but the noise steadily increased. I arose and argued about trifles, in a high key and with violent gesticulations; but the noise steadily increased. Why would they not be gone? I paced the floor to and fro with heavy strides, as if excited to fury by the observations of the men –but the noise steadily increased. Oh God! what could I do? I foamed –I raved –I swore! I swung the chair upon which I had been sitting, and grated it upon the boards, but the noise arose over all and continually increased. It grew louder –louder –louder! And still the men chatted pleasantly, and smiled. Was it possible they heard not? Almighty God! –no, no! They heard! –they suspected! –they knew! –they were making a mockery of my horror!-this I thought, and this I think. But anything was better than this agony! Anything was more tolerable than this derision! I could bear those hypocritical smiles no longer! I felt that I must scream or die! and now –again! –hark! louder! louder! louder! louder!

    “Villains!” I shrieked, “dissemble no more! I admit the deed! –tear up the planks! here, here! –It is the beating of his hideous heart!”

    1. I really think that’s the least likely explanation. It may be a h’ant, but there’s no room for a heart in there.

    2. Was that from the Tell-Tale Japanese-Car Overhead-Cam Engine Replacement Timing Belt?

11. Noisy HD or are you running a SSD?

    1. It’s an SSD. My hard drive is sitting on the desk, outside the case. That’s not the source of the noise.

12. That recording sounds like a rotary printing press or old tractor engine. If you’re running a SSD and have eliminated and fans in the case as the source, I have to wonder if something is resonating with an external source of vibration. You might go through and make sure every last screw and fastener in the computer is properly tightened.

    1. It’s definitely a resonance, but I think it has to be between the case and the CPU fan. Not sure what to do. I’ve tightened every fastener I can find in the machine, and pressured every point. I’;ve also lifted and held the case off the desk, which mitigates it somewhat. It is definitely some interaction between the internal dynamics of the case and the external environment, but it’s very subtle.

13. Are you on a submarine? It honestly sounds a lot like the caterpillar drive sound from the movie adaptation of The Hunt for Red October, and/or resonance from a marine diesel engine.

    That said, does your house use geothermal temperature control and/or a well? It could be a well pump resonance of some sort traveling through the house.

    In any regard, it could be the case itself has seam fitment issues or clearance issues, or a screw or Tic-tac or paper clip or other small bit of something dropped and fell in somewhere that it doesn’t belong and it’s rattling in a hidden spot inside the case. Some disassembly required.

    1. It honestly sounds a lot like the caterpillar drive sound from the movie adaptation of The Hunt for Red October, and/or resonance from a marine diesel engine.

       I know. It’s not that loud, but it is definitely a resonance of some sort, probably with the CPU fan. I just can’t figure out what is loose enough to allow it to happen.

14. If it’s a motherboard vibration thing, one way to fix that is to lift the MB, and slip a thin sheet of foam mailer packing material under it, then tighten it down.

    1. I may resort to that, but I’ve been trying to avoid it.

       1. If it is the CPU fan, your only option may be to replace the entire heatsink/fan combination with a new _and different_ model. With any other fan you could use a rubber or silicone grommet/gasket, but I’m not sure how that would work with a CPU fan. (In my experience, though, it’s more likely the fan itself would have a bad bearing than that it heterodynes with the heat sink.)

          If you are willing to spend a bit of extra money, you could buy a closed-loop liquid cooler. It’d be quieter than the fan.

15. So it was a fan after all.

    You can always get a new case. A mid-tower case is usually pretty cheap. Most of the cost is usually the power supply not the case proper.

    http://www.newegg.com/Product/Product.aspx?Item=N82E1681115409

    This one is $29.99 USD it probably costs more to transport than to buy.

    There should be an easy way to change the fan though. Check if you can access the fan sideways, or pop out the front panel, or something.

    1. Or maybe that drive cage can be removed somehow.

       1. The drive cage can be removed by drilling out the rivets. No thanks.

    2. I took the front panel off. All that does is allow me to remove screws that hold it in. There’s no way to get it out. And it’s larger than standard. If I ever close the case I’ll stick one in the rear slot.

16. Rand, if you decide you need a fan there (See what your chipset temps are like without it first.. perhaps you don’t.) IMHO it’s be far easier to simply piggy back a fan into that area than getting the cage apart.

    For a couple of years, I had one installed with duct tape. It worked fine.

    1. I’ve been running without it all day, no problem. But I’ve also had the side missing from the case for many months. There is a place to install one in the rear if I want to (finally) close up the case. I even have one to put in. I’ve abandoned it, and as far as I’m concerned, problem solved. It will be truly solved, ultimately, when I replace the case.

    2. I’ve been running without it all day, no problem. But I’ve also had the side missing from the case for many months. There is a place to install one in the rear if I want to (finally) close up the case. I even have one to put in. I’ve abandoned it, and as far as I’m concerned, problem solved. It will be truly solved, ultimately, when I replace the case.

       Also, just read the first part of that. Piggybacking sounds like even more of a nightmare, given the clearances.

17. “There is a huge case fan in the front that I had previously been unaware existed.”

    I had a feeling that would be the case, but you insisted you didn’t have any others. 🙂 It almost _had_ to be a fan.

    1. I insisted I had no others, because I had previously been completely unaware of its existence. It wasn’t obvious until it failed and I had to tear the machine apart to search for it.

18. {facepalm} Really? REALLY?

    I guess I had higher expectations, like maybe you’d know where all of the fans are in your case.

    Failure is definitely an option here.

    1. Sorry, but I had to pull the machine from where it was to figure it out. Why would someone automatically know where all the fans were without having previously investigated? I put an MB in, it worked for years.

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