19

My CPU produces a noise when it's at a certain frequency.

I noticed that when I set my mouse to a 500 Hz polling frequency and move it in circles, the CPU noise practically disappears. Using lower polling frequencies (200-300 Hz) doesn't have the same silencing effect. This also happens with four different (new) PCs at my house, so I assume it's not some kind of defect.

As I don't want to constantly move my mouse, I am looking for a way to send a constant polling signal of at least 500 Hz to my computer, such that the CPU is "silenced".

What kind of device or software can help me achieve this goal?

Edit 1:
Creating artificial load to the CPU has no silencing effect anymore after the general CPU load has increased further. This probably means it can never serve as an effective method to reduce CPU noise.

Edit 2:
Many suggestions here. I'm currently investigating what is really happening in my specific situation.

Edit 3:
Turned out that this noise issue is most likely a manufacturer problem.
I decided to inform AMD through their online service request system
about my problems with their Ryzen 7 Pro 5750G models.
The trigger for the noise was the AMD Ryzen 7 PRO 5650G model that is actually integrated into all 4 PC's.
I recently contacted the company who originally assembled these Win 10 desktop systems for us to let their IT specialists analyse this specific issue with own testing machines.
They generally confirmed my observations and informed me that only the AMD and board manufacturers are capable to eventually provide a solution in the future. Specialists confirmed increased motherboard noise while mice are used to zoom/rotate objects in Blender if the Blender application window(the same behaviour in Autodesk Maya) is significantly larger than 640x480px.
In addition they noticed that specific motherboard models and even "duplicates of the exact same model" produced constant noises in Windows as long as the "Global C States" option in BIOS is activated for all the 5750G's.
Because they identified the specific processor model 5750G from AMD as the trigger for the increased motherboard noise and because this very disruptive noise behaviour has negatively impacted my workflow with 3D modeling applications, we decided to upgrade.
This time all motherboards are going to be replaced with B660 boards from MSI and we chose INTEL Core i7-12700's including new CPU coolers to safely avoid this issue.

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  • 15
    What are you trying to accomplish?
    – Daniel B
    May 4 at 14:18
  • 8
    In other words, you're trying to get rid of "coil whine"?
    – user1686
    May 4 at 14:37
  • 4
    Electromagnetically induced acoustic noise, aka : "Coil whine". There's no magic bullet. When your CPU is doing something different, running a different application, is under different load, the sound will continue to change. There is no "software" way to fix this that isn't ad-hoc and fragile. You can replace your motherboard with a better model or otherwise use your ears to try to hunt down the inductors responsible and damp them with something like hot glue or silicone. Careful they don't overheat if you do...
    – J...
    May 5 at 0:10
  • 28
    Also, it is almost definitely not the CPU making this noise, but a different component in your computer. The CPU is a small chip, a very important one, but not one that produces coil whine. May 5 at 4:28
  • 28
    For some reason your question reminds me of this xkcd. I'm not sure why, but it may be the "That's horrifying" line.
    – gronostaj
    May 5 at 10:49

4 Answers 4

17

Is there [...] anything (a device) that doesn't require my manual input

You can use any Arduino based on the ATmega32u4 to emulate a mouse (or keyboard) and send data every 2 ms (i.e. 500 times a second).

There are also Arduino libraries for doing this with any ATtiny85 such as the Digispark and cheap clones of it - this is slightly harder to work with though.

Digispark]
source

You could probably do the same with a Raspberry Pi Pico - which might be cheaper (around $4).

https://www.recantha.co.uk/blog/?p=20836

Having said that, I think it would be much better to identify and fix the cause of the noise in the PC.

8
  • Thanks for the advice. I tried this - actually I spent 3 months to identify the cause of this problem. I completely rebuilt every part of one of my 4 PC systems, another new ssd/cpu/gpu/psu/fans/cables/sdd/motherboard. It doesn't make any difference - this noise is noticeable with all machines. Somehow it must be my house/location that let my cpus run at this "other" standard frequency that produces relatively loud noises/sparkling/buzzing. I'm not sure what I can do otherwise.
    – atereou
    May 4 at 15:14
  • About your answer - is one of these solutions capable to not affect/influence my mouse cursor while sending at 500 Hz? I wonder what's a good option for me here.
    – atereou
    May 4 at 15:18
  • 1
    You would have to find some mouse action or report which can be sent without significantly affecting your use of the main (real) mouse. For example there may be support for pressing extra buttons which your mouse does not have and which have no function defined in your application. Maybe just release the middle button without ever pressing it. Or maybe just move the mouse one pixel and back. May 4 at 15:30
  • 17
    Your CPU frequency (several GHz) is inaudible. More likely a PSU producing mains hum at 50 or 60 Hz? May 4 at 15:37
  • Thanks. So this means even such a "not-available-by-my-mouse function" is able to actually send at 500Hz frequently - is this correct?
    – atereou
    May 4 at 15:37
31

As other's have noted, if you've observed this behavior from multiple PCs in your home, the problem is most likely with your incoming power utility rather than any of the PCs.
Coil-whine is a well established phenomenon of electrical circuitry attempting to filter electrical noise from the power supply.

The answer Chris Woods offered has an excellent suggestion to start by going through your home and removing power from your appliances until you observe the problem going away. As stated this may identify a local source of the interference.
As suggested by Chris Woods, in the event that you are unable to locate the source of the interference, you might consider investing in a UPS for it's power-filtering capabilities. This has the added bonus of protecting the machine plugged into it in the event of unexpected power failure.
Another consideration of note would be a line conditioner - it does a comparable level of power-filtering as the UPS, however this is all it does - it takes no batteries and offers no protection from events which interrupt your power. This makes it slightly more friendly to the budget for the purposes of shipping, and low-overhead for maintenance as you have no batteries to be concerned with.
Regardless of whether you purchase a UPS or a plain line conditioner, ensure that you invest in a unit which has sufficient current capacity to support each device you wish to apply line filtering to. If you have multiple devices that are far enough apart, you may even consider purchasing multiple smaller UPS/line conditioners than a single large one.

14

The issue sounds more to do with your property's incoming utility supply, or some other device with a poorly designed PSU producing feedback onto your property's supply. You may also be very unlucky and be living next to a neighbour whose faulty or badly-designed equipment is impinging on your supply, if you have a weird or outdated power distribution to your properties. This can also happen if their electrics are in poor condition and you share a local drop from the street supply. (I've heard several stories about Christmas tree light power supplies or dodgy CCTV camera power supplies causing interference with WiFi, radio/TV reception, or noise on mains supplies to other parts of a building).

EMI and coil whine is an annoying problem sometimes without a quick solution.

Incidentally worth a watch:
https://www.youtube.com/watch?v=yDX_1PWUWdw (they discuss at one point the effect of other poorly-designed devices on a mains supply)
https://www.youtube.com/watch?v=t6E0O8UtObU (this is a real doozie)

Which country are you in? Your utility provider may be able to assist if you can prove the noise is not limited to just one device. Might not hurt to ask your neighbours if they also notice this problem with their PCs, or if they've noticed any problems with power supplies.

How is your breaker box / consumer unit (aka fusebox)? Do you hear it humming or buzzing particularly loudly? If so you may have a residual issue which would require a qualified electrician to inspect and fix.

You mentioned 500 Hz which implies you're possibly not in the USA given that's a multiple of UK/European/some ASEAN countries' mains voltage frequency. If you plug the computer in on another ringmain (UK) or branch circuit (US/elsewhere), do you still get the EMI/coil whine?

You could also start by going round your house and physically unplugging everything, listening for the noise while gradually plugging everything back in. That might identify the culprit.

Also, have you considered buying a quality UPS which can also do Active Power Factor correction (important for modern PSUs), to produce a clean isolated supply of AC? I use a Cyberpower CP1300EPFCLCD. Not cheap, but worth every penny, it's saved my equipment from multiple blackout and brownout events in the last 18 months.

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  • 12
    "This also happens with 4 different (new) PC's at my house" - then the problem is your house, +1.
    – Mazura
    May 5 at 2:12
  • 2
    To add on to this - I'd start with shutting off every single breaker in your house - then turn on one circuit breaker at a time and see if you can isolate it to a certain circuit or device. Move your computer to different circuits as you switch them on/off to see if it follows you. Other than that - do you live near any cell phone antennas or high-voltage power lines?
    – montjoy
    May 5 at 2:41
  • 5
    500Hz isn't the AC line frequency (anywhere in the world), it's the mouse sample-rate for reporting position updates to the computer. (Some gaming mice run that fast or faster for lower latency and to better capture the shape of fast movements. And because it's a marketing number.) Faster mouse updates would run a USB interrupt handler more often, maybe preventing the CPU from doing into as deep a sleep state in between. May 5 at 4:27
  • 1
    You could verify what @PeterCordes is suggesting by using a utility such as CPU-Z to monitor the state of your CPU (i.e. core frequency is the current speed the CPU is running at). Does the noise change as the core frequency changes. May 5 at 22:29
  • @PeterCordes 500 Hz is however a multiple of 50 Hz, AC frequency in the UK and other countries. In one house with bad wiring where I was trying to do sound recordings, I had to deal with audible harmonics into the high hundreds of Hz. Unclean AC into a struggling PSU or mobo VRM might be causing secondary noise. Very true what you say about mouse poll rates though, my mouse runs at a similar refresh. May 12 at 19:48
9

This noise is an artifact of how the power-saving features of your computer operate.

Very simplified picture:

When there is little load imposed on the CPU, the CPU lowers its clock frequency. This has a complex logic, usually done in both hardware and software. The voltage powering the CPU is lowered as well.

Then again, lowering the clock frequency and the voltage has some practical limits in saving power.

When the load is even less (the computer is absolutely idle), it becomes advantageous from the power saving standpoint to absolutely power off parts of the CPU for a while.

This "while" is like 0.0009s, followed by like 0.00001s of activity. The numbers are made up, but pretty much possible.

This sequence of powering up/down generates current pulses in the power rails, as well as power supply inductors, who change their shape and size by a tiny bit. While their main operating frequencies are 10^5 - 10^6Hz (absolutely inaudible), the above scenario generates 1kHz (right at the maximum of the human ear sensitivity).

And this is the sound you hear.

One can simply disable this power saving feature in and the sound will completely disappear.

But the consumed power in the idle state will be a lot higher.

What you intend to do is to create an artificial load to the CPU. This may also work, but is even less reasonable.

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