Where is coil whine coming from

[LV_gamer]

I am having very audible coil whine coming from my pc but I don't know from where exactly.

It's probably from either my GPU or the power supply but I can't distinguish wich one.

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My specs:
CPU : Core I5 7500
Motherboard : Gigabyte h270-hd3
GPU : Gigabyte GTX 750 TI Windforce OC 4gb
PSU : Tecnoware Core 550 550W

If needed I can post some temp and power readings.

 

[mazboy]

use the screwdriver-as-stethoscope method. Touch the metal end of a screwdriver to what you think is making the noise, and the plastic end against your ear. You should be able to track down the whine that way. Be sure not to touch anything "hot" like bare wires/traces, etc.

 

[mbarnes86]

Hi


Is the noise there all the time or only when the GPU is working hard?

If it is there all the time and you have a Intel CPU with integrated graphics you can easily remove the GTX 750, connect the motherboard to the screen and see if the coil whine is still there

If it only happens when the GPU is working hard it could still be the GPU or PSU

are you sure it is coil whine and not fan noise?

regards
Mike Barnes

 

[LV_gamer]

I's only when under a load.
It can't be fan noise because I have all my fans running at really low RPM. https://imgur.com/a/ivgAD

 

[Mark_1970]

I's only when under a load.
It can't be fan noise because I have all my fans running at really low RPM. https://imgur.com/a/ivgAD

I find coil whine ( wires on coils vibrate) happens at certain visual resolutions, like on a cutscene during a game it will be loud as the scene is displayed at say 800x600 dpi. Many psu's will do this. Fairly common and nothing to worry about. Packing hotglue around these coils can quieten them as some psu makers do just that . PS.... That psu is kinda junk. Sometimes the coil wire was wrapped a little loose, Probably used cheap coils maybe

"Filtered Pulse Width Modulation is what regulates the voltage. Your PSU, GPU, and motherboard (providing individual power to the CPU, DRAM, and chipset) all use PWM.

The "coil whine" will not necessarily be coming from any particular source; it could come from any of those sources. But, the GPU typically is the source of noise because it is low voltage (around 1 volt) at high wattage which equates to higher amperage than the other PWM sources.

The PSU is obviously pushing out the same combined wattage to the motherboard, GPU, and other hardware. But the PSU is providing power at higher voltage (primarily 5v and 12v) which equates to lower amperage flowing through the PWM voltage regulation filters in the PSU.

Inductors in the voltage regulator circuitry are coils of wire which are part of the output filtering which vibrate due to pulsating magnetic fields generated as current flows through them. You can hear them vibrate like a speaker if they do at a high enough amplitude.

Preventing coil whine is ultimately up to the manufacturer when they design the hardware. They can either use higher quality components which are less likely to make audible noise, or add more power phases so that less current is flowing through each specific phase thereby reducing the amplitude of the sound.

Interestingly, since the PSU is providing PWM regulated and filtered output to every part of your computer, the CPU, DRAM, chipset, and GPU effectively have two layers of PWM voltage regulation to them. A low quality PSU with "noisy" voltage output (poorly filtered), can aggrevate the PWM voltage regulators on the motherboard and GPU. Coil whine on a GPU can sometimes be dramatically reduced by purchasing a better PSU which has more stable voltage output."