[SOLVED] Coil whine coming from a CPU cooler?

[turner3d]

I have read over and over that coil whine coming from a CPU cooler is not possible, not really a thing. I have heard the same advice that "some fans just emit a sound at certain RPMs," etc, even here on Tom's. I had something extremely similar to coil whine coming out of a CPU cooler, and would just like people to be aware that this is possible. I have since replaced the cooler, the chirping is gone, and my sanity is restored. I am posting this only as evidence. For reference, this is an old ASRock 970 Extreme4 mobo with an AMD FX-8300 and a stock cooler.

The system was emitting a high-frequency scratching/chirping noise would perfectly accompany pretty much anything happening on the monitor; highlighting text, opening windows, closing windows, watching video, anything that changes pixel content (regardless of frame rate). Because of this, I assumed that it was my video card and that I was stuck with it, having read so many times that there's nothing you can really do about it in a GPU.

When I finally got sticking my head in the system and poking around, I was extremely surprised to be able to mute the chirping by gently touching the CPU cooler. Unplugging the cooler (only for a few seconds, of course) also made it go away. I made a short video to demonstrate, putting up a youtube video on the screen so that pixels would be changing and it would chirp unassisted. (Note that I had to touch up the audio channel a lot - cranked up level, added some compression, eq'ed out bottom end. Please forgive the background noise coming from my family).

Fans obviously have coils, but I'm not sure how or why this would happen. Is it possible that the video card's variation in drain on system power could cause the circuit powering the fan (already PWM, by the way) to modulate to the point of being audible? Is this technically coil whine, or something else?

 

[JohnBonhamsGhost]

if it's coming from a fan; than it is sounds produced by the bearings going bad or lacking sufficient lubrication, blades being unbalanced, or something possibly rubbing(internally or externally).

if it is coming from a static device(with no moving parts) than it may be coil whine.

to test if it is actually coming from a certain fan;
while the sound is being produced lightly press on the center of each fan. if the sound stops as a particular fan stops rotating, it is that fan.

 

[turner3d]

Thanks for the advice, but you obviously did not watch the video. The fan has been pinpointed as is clearly demonstrated. Also, the sound is absolutely not mechanical in nature. That is, it is not being caused by rubbing, chafing, lack of lubrication, or anything of the kind. If you listen closely to the sound in the video, you will hear that the chirping stops the instant that the fan is unplugged, and the pitch of the sound is consistent even as the fan is spinning up. I realize it is hard to tell from the sound in this video recorded on a phone and without being here to be able to observe the absolute connection between the sound and what is happening on the monitor.

 

[JohnBonhamsGhost]

Thanks for the advice, but you obviously did not watch the video.

i watched and hear nothing but a constant annoying fan sound, like a cheap and/or malfunctioning fan.
when you unplug the CPU fan the sound quiets some but there is still an audible constant sound like another cheap fan running.
i hear no intermittent "chirp".

 

[turner3d]

As I mentioned previously, I greatly modified the audio channel so that what I was talking about would be audible without turning your volume up all the way and strain to hear what I was referring to. I guess the process not only greatly amplified, but really changed the nature of every other sound in there. The other fan you're hearing is the stock cooler from an R9 290. This is the original video with unaltered audio for reference/comparison:

I don't believe I ever mentioned anything about the sound being intermittent; it's more like a single high pitch around 3 KHz which modulates as pixels change on the monitor. I had a muted youtube video playing while I was recording this so that the "chirping" would be pretty consistent. I promise you that the sound is not being caused by parts rubbing, bad bearings/bushings, or anything physical; it is digital in nature and directly tied to changes in the video output, somehow. The only way I could truly demonstrate this would be to capture what was happening on the monitor while recording audio from a mic next to the cooler, but you will just have to take my word for it since I will not be uninstalling the new cooler and reinstalling the old one just to make another video.

 

[JohnBonhamsGhost]

Is it possible that the video card's variation in drain on system power could cause the circuit powering the fan (already PWM, by the way) to modulate to the point of being audible?

your dedicated R9 290 draws power directly from the PSU. so it's variation in power drawn wouldn't affect the motherboard or other onboard components, unless you have a very cheaply produced and unreliable power supply that cannot handle the GPU efficiently and in turn varies the output to other devices.

if this was the issue; replacing the CPU's fan and/or cooler wouldn't resolve the issue. it would be persistent until changing the PSU or removing the GPU.

The system was emitting a high-frequency scratching/chirping noise...

I don't believe I ever mentioned anything about the sound being intermittent

"chirping" means an intermittent high-pitched noise. a constant sound is not a chirp.

 

[turner3d]

Ok. Definitely not the power supply - SirTec 1200W PSU in great condition, and as you mentioned, changing the cooler made the issue go away, so not that.

I don't know if there is a good name for the sound - that's why I posted video. To reiterate, these are the facts:

1. 3 KHz-ish "chirps" (or whatever) coming from CPU cooler
2. These sounds correspond with video card activity, not just high framerate; literally sounds made whenever pixels change content
3. PSU is good
4. Replacing cooler made sound go away, so definitely cooler

So, after all of that, can be labelled as coil whine? If not, is it a known phenomenon? What on Earth might cause it?

___
background only past this point, and only because I've had a couple of beers and don't need to have my gear insulted anymore

Until about a month ago, this rig had been sitting in my attic for about 5 years. It was originally put together as a cryptocurrenty-mining rig in January 2014 with the following specs:

• ASRock 970 Extreme4 mobo
• AMD Sempron 145 crap processor
• 8GB DDR3
• 3 x Sapphire R9 290 GPUs
• SirTec 1200W PSU

It was actually built completely open-air in crates I picked up from Home Depot for $5 each because it was built for OC speed, not for looks. I made a decent chunk of change in the mining world, but decided to pull the plug as it became more popular and the electric bill started outweighing the profits.

Anyway, then came the COVID19 lockdown. Having to work from home, I was faced with having to compete for the desktop PC with my wife and my son who needed it for school. I was in the process of figuring out what I was going to buy as a 2nd PC when it hit me - I have a computer of sorts in the attic, a wireless keyboard & mouse I bought to interface with a modded original Xbox back in like 2003, and a recent & decent 75" 4k TV with an HDMI input - no need to buy anything new! I reconfigured the mining rig a bit, stripped it down to a single GPU, installed windows 10, and we're off to the races.

Initially, it had only a Sempron 145 CPU which was honestly complete crap, but it didn't matter for a mining rig; all of the work was done by the GPUs. In early 2014, R9 290s were the shiznit in that department. Since installing it in the media room, I have upgraded the processor to an FX-8300 (just about the highest processor supported by the mobo, and I had to order it from China - been out of production for a while, but found one for $62), replaced the HDD with a SanDisk Ultra SSD, replaced the CPU cooler (the topic of the post) and am currently waiting on delivery of an ARCTIC Accelero Xtreme III to replace the overly-noisy stock cooler on the 290. That's upgraded just about as far as it will go without getting a new mobo and starting over with everything.

 

[Karadjgne]

That's not coil whine. That's the aluminium fins of the heatsink reacting to a slightly out of balance fan. When you put pressure on the fan housing, the noise went away. I'd suspect there's 1 or more fins that are not tight to the fan shroud, just barely touching, and are vibrating.

Take a regular wooden toothpick, 2 of them, snap in half and stick them catty-corner between the fan and heatsink, right next to the 4x screws that hold the fan to the heatsink. Won't hurt performance in the slightest. Sound should go away.

And yes, coil whine is a real thing in any electric motor, whether it's a fan or not, since an electric motor is nothing more than 2 giant coils anyway.

 

[turner3d]

I must disagree, Karadjgne - I can see how it seems mechanical from just watching, but it is not - the sound only happens when pixels are being changed. To capture the sound being made, I had a youtube video playing so that the noise would be audible with no interaction. I get that this thread has already gotten a little TL;DR; but all of these things have already been covered more than once.