Audible Buzz from Z170 Gaming 7 MoBo

[JefeSteeze]

Hello All,

This is my first post here (obviously). I read the F.A.Q. and did a search for this problem, but nothing came up. My new Skylake rig buzzes loudly through both the headphone jack and the MoBo ports. First the rig, then some details:

Gigabyte Z170 Gaming 7 Rev 1.0 (F5 firmware)
i7 6700k at stock clocks
Corsair H50 CPU cooler
Fractal Design R5 Silent case
EVGA GTX 970 SC at stock clocks
EVGA SuperNova 750w Bronze PSU
Corsair Vengeance 2x8 GB DDR4 @ 3000 Mhz
Behringer UCA202 DAC

Issue 1: When I plug my headphones into either the 3.5mm headphone out jack on the front of the case, or in the back of the MoBo, I get a very audible whining sound. I tried with multiple headphones and an amp and determined it is definitely the computer.

Troubleshooting:
My first thought was coil whine from the GTX 970 so I had that RMA'd and installed a replacement. That did 'reduce' the issue, but did not solve it. Also, the higher the FPS in the application the louder the whine. So the buzzing IS coming from the 970, but at this point I've tried 3 of them with the same issue. Also, there is no audible coil whine when it's running, even with the case open, I can only hear it through the headphone out.

So my next solution was to buy a cheap USB DAC, however that actually makes the whine significantly worse! I plugged the Behringer into every USB port on the Mobo (including the front case ports and both dedicated DAC USB ports on the mobo itself) and the whine is TERRIBLE. When I hook up my speakers to it (audiophile grade amp + speakers, costs more than my PC) the whine is so intense that I can hear it loudly even when the amp is on a different analog input. Even touching the DAC to my amp sets the thing off like crazy, so somehow the buzzing is transmitting up the long USB cable and causing the DAC to go nuts.

My third solution was to use the 3.5mm out on my P.O.S. Asus monitor. Once again, the whine is horrible, worse than the 3.5mm jacks on the PC itself.

In sum:
NO audible whine from case, it's whisper quiet
Whine source is almost definitely the graphics card
Audible whine from 3.5mm Headphone jacks on PC
VERY audible whine from USB DAC, even from the dedicated DAC USB ports...
VERY audible whine coming through the HDMI out of the graphics card
VERY audible whine coming from the HDMI of the mobo (I hooked up the cable, got not video/audio but got a significant whine by touching my headphones to the monitor)

So, if the problem is the graphics card, why am I posting here? Because correct me if I am wrong but I don't think the MoBo should be allowing that whine to penetrate all of the other ports, especially the DAC USB ports. Also, usually when coil whine is a problem on graphics cards you can hear it audibly. I can't hear any whining or buzzing from the PC, even when I take the side off the case and stick half my head in there. So I think the coil whine on my 970's is pretty minor, and the MoBo is somehow amplifying this out of every port on my PC.

Has anybody got any ideas?

Thanks,
Jefe

[absic]

Hi,

sorry I can't say why you are getting this noise but my first thought would be that it is something to do with the on-board audio.

I don't know if this will help but in the BIOS under ChipSet - Audio Controller - the Audio DSP line is set to Enabled by default, try setting this to disabled to see what happens.

[JefeSteeze]

Yeah, it's definitely possible the onboard audio is at fault! But if the onboard audio was messing up, why would that affect:

Audio via HDMI
Audio via USB DAC

Also, the buzz increases and decreases with framerate in games. So I play a lot of CS:GO (average FPS ~250) and Fallout 4 (average FPS 60-100). When I play CS:GO, the buzz is noticeably worse, and increases as the FPS increases (it regularly jumps between 100-300). So the graphics card is the source of the whine, the MoBo is just transmitting it out of any/everything that connects to it.

I'll definitely try disabling the Audio DSP in the BIOS tonight though, will post back and let you know what happens. Yes, that is what I plan to do with my Friday night...

[absic]

Another thing to try would be changing the slot the graphic card is installed into on the motherboard, to see if that alters the noise you are getting. I know you wouldn't be getting the full speed from the GPU but, it might help isolate the cause of the problem.

There is also a newer beta BIOS over at TweakTown here:http://forums.tweaktown.com/gigabyte/28441-gigabyte-latest-beta-bios.html F6j which I would also try.