79XX-coil whine. True or false?

[rjk]

Does anyone even know the science behind the coils whining? Why don't we ever hear of motherboards whining? Only GPU and PSUs.

The answer is right here:

To have coil whine you need a coil and those are in your PSU.  

... I guess Graphics cards must also have them?

Coil whine is caused by resonant frequencies in an inductor (coil). All electronic components with their own PWM regulated power supplies such as motherboards, graphics cards, and other peripherals have such coils (AKA chokes), even though they may only be the size of a standard capacitor. Here is an example of a very small one that you might find on a motherboard (from digi-key):



And here is an assortment of coils, large and small:

[1714151250]

1714151250

[1714151250]

1714151250

[1714151250]

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[1714151250]

1714151250

[AzN1337c0d3r]

I have 3x 7970s on water-blocks and I can't hear a peep out of them.

[twoBitBasher]

There are too many factors involved here. How loud the whine is, is relative, and also it greatly depends on the model of the video card. On a few of mine, it ranges from no noise at all, or barely audible. On others, there is obvious whine, to squealing. I also noticed that when the mining application stops, it also stops squealing.

Have you guys noticed any difference between miners? cgminer for one makes one of my 5870s whine quite audibly. phoenix not so much as a peep. There seems to be also a good 40w difference on power consumption. Yet the throughput seems largely unaffected. I run with water so not too much fan noise to cover the whine, but I bet one could hear this whine despite the fan noise of stock cooling!

So the real question is why don't the other cards whine? Does this have anything to do with too low voltage(11.6v measured from whining card's power cable connector)? Can my caps blow up?

[rjk]

There are too many factors involved here. How loud the whine is, is relative, and also it greatly depends on the model of the video card. On a few of mine, it ranges from no noise at all, or barely audible. On others, there is obvious whine, to squealing. I also noticed that when the mining application stops, it also stops squealing.

Have you guys noticed any difference between miners? cgminer for one makes one of my 5870s whine quite audibly. phoenix not so much as a peep. There seems to be also a good 40w difference on power consumption. Yet the throughput seems largely unaffected. I run with water so not too much fan noise to cover the whine, but I bet one could hear this whine despite the fan noise of stock cooling!

So the real question is why don't the other cards whine? Does this have anything to do with too low voltage(11.6v measured from whining card's power cable connector)? Can my caps blow up?

Likely due to the quality of the inductors in use on the card, although they probably won't fail. As someone else mentioned, you could try dropping some superglue into any chokes that you find, to see if a slightly loose winding is resonating.

[twoBitBasher]

Umm I had connected this particular card via the 6pin-4pin molex adaptors that was included in the box. Now I changed it to better cables. I measured the voltage under load before and after I changed. The second connector actually had a lot lower voltage of 11.4v vs 11.6 with the new cable it is 12.05v on both connectors and the whine is almost gone.

I don't think it is the chokes because I can't see any of those in the area the whining seems to emanate(rear end, next to the 6pin connectors). I can only see four caps.

However as I'm not electronics guru would someone with more knowledge explain why the whine almost went away when the card got more juice while the load remained the same.