Coil whine from AB350 Gaming motherboard

[pfolzini]

Hi everyone,
After few months of "silent" use, my AB350 Gaming motherboard started to make COIL noise ONLY WHEN I ENABLE LAN CARD. The weird thing is that I've 2 lan cards: one on the board and another Intel card on a PCIex slot: the noise comes from each of them (worse on the board port). I've tried every single component (it was possible because I'm an IT technician). At the beginning I thought the sound was coming out from the GPU (MSI 1060 Gaming), because I tried a smaller card (GT730) and had no noise, but when I changed it with an old HD 5870 the coil whine was worse. Tried also to change my Enermax Evolution 750W with a corsair TX750: no result.
Other considerations: with F10 bios release and "global C-state disabled" the situation is better but not solved. I know it sounds strange, but NO LAN ENABLED...NO COIL WHINE.
Thanx for any help
Paolo

My PC:
CPU: 1700 AMD Ryzen
MB: Gigabyte AB350 Gaming
GPU: MSI 1060 Gaming X 3GB
RAM: Kingston Fury X 2400Mhz (2x8)
HDD1: Samsung 850 EVO 512GB
HDD2: WD Black 1TB
PS: Enermax Evolution XT 750W

[shadowsports]

Dealing with harmonic vibration.  Are you certain the power being supplied to the PSU is stable, free from fluctuations and spikes?    If you've replaced all components, tried a different PSU and still get whine, your board might not be functioning properly, or has an issues with tolerances or manufacturing.  Often its related to component choice, but once you have it, there's almost no way to get rid of it. Not looking good if you have replaced most everything and can only solve by disabling an onboard peripheral. 

   

[pfolzini]

Thanx for reply, as I said the PSU is the first thing I changed (tried corsair TX750) with no result. There's something wrong in the "part" dealing with LAN chipset. I also disconnected all case fans.
I'm open to your ideas 
paolo

[shadowsports]

Thanx for reply, as I said the PSU is the first thing I changed (tried corsair TX750) with no result. There's something wrong in the "part" dealing with LAN chipset. I also disconnected all case fans.
I'm open to your ideas 
paolo

Greetings,
I understand you changed the PSU.  I'm talking about the power being fed to the PSU.

What happens of you move the machine to a different power source?  I suspect it will follow since you said the board had been silent initially.

I also re-read your original post.  So the board whines when onboard LAN is enabled in BIOS regardless of what other peripherals or devices you have installed and connected?  You've tried with the Add-On LAN card removed, right?  It's just a little more quiet?

While I believe this is a physical anomaly, to be thorough you should try CLR_CMOS and retesting. 

You can also try bench testing the board removing it from the case.  Depending on the results, I would look into RMA.  But do keep in mind that in 90% of cases, coil whine is the result of component selection.

[pfolzini]

Thanx for your interest and suggestion, I've partially solved the problem. Let me explain:
- I've tried a different electric source...nothing
- I've removed the PCI LAN card (an Intel CT card also used on servers) and only used the integrated one (it cannot be disabled from bios!!!!)... coil whine worse than ever and 2 "mouse freezing" with Chrome (restart with power button).
- changed the pci slot for VGA and used the second one...no change.
LAST CHANCE: used the sylincon glue covering CAPACITORS in the motherboard where I listen to the noise louder; here a video about a PSU and the usage of sylicon glue:
https://www.youtube.com/watch?v=ENXKpRdQQnA&index=1&t=163s&list=FLOw4AdBsPAz--PIuf5qopjg
After that the noise became very low, but I understand I solved the symptom, not the cause of the problem (the 2 crashes or freezes with integrated LAN card make me think there's a problem on the board)
Conclusion: with my "gluing" the board is almost silent, but probably out of warranty; I'll use it for office work, but in these hours I've ordered a X370 board.
Thanx again
Paolo

PS: I'm not suggesting to use glue: sometimes the coil whine is simply an annoying noise, sometimes the symptom of an electrical stress or an old capacitor

[pfolzini]

Final considerations:
I wanted to buy Ryzen 1700 (a beautiful CPU), just 3 weeks after its commercial launch. It's my opinion the first 6 months are for "beta commercial testing". Now you can find a lot of reviews about ryzen boards, 8 months ago no

[shadowsports]

The Ryzen is a great processor and a great fit for people who are looking for power and flexibility on a budget.  I think it really caught Intel off guard which is what prompted coffeelake's release pre 2018 as their roadmap initially indicated.