New "Build" buzzing from LG OLED..

[faxfan]

Here's a good one....

I've been playing on a laptop on the TV in the living room (HP omen 1060 @ 1080p / 60) and everything is peachy. Apart from the super loud fans on the lappy. So... ordered some bits from overclockers, stuck in some spare bits to create a "HTPC", but I'm getting an incredible buzzing feedback related to the refresh rates from the PC to the OLED.

Specs -
Mini ITX mobo (ROG Strix 360)
Titan Xp
Seasonic PSU (650w)
LG OLED C7
HDMI connection

Symptoms -
4k x 2k, 60Hz - very very loud buzzing feedback - not sound related can mute sound and it's still there.
1080p @ 120Hz - very loud buzzing
1080p @ 60Hz - loud buzzing
1080p @ 30Hz - virtually silent buzzing....


I've swapped power cable, power cable locations, HDMI cable, HDMI ports (via AVR and TV) all the same. Laptop seems to behave ok (not sure if it's having 2nd screen or something, haven't tested multi displays yet).

Any ideas what to check / change???!?

 

[LuckyBenski]

Sounds like coil whine. My system does this whenever the framerate increases. Happens in menu/loading screens or when I minimize benchmarks for some reason.

It may be a symptom of the card itself or possibly could be the power supply. Are you using separate cables for each PCIe power connector?

I'm guessing you have Vsync turned on if running those limited framerates?

 

[faxfan]

Well, this was interesting one. I have number of devices running on the power on one side of the room - TV, Sky Q, PS4, 4K blu ray, AMP, 2 x Power AMP and 2 lamps. If I run an extension lead from the other side of the room and power up the PC there is no buzzing / humming feedback at all. No issues with any of the existing kit at all, I can only assume something in the PC sensitive to power, I could through all the devices or just use a very long extension cable (I can easily hide it)!

 

[EsaT]

Sounds like some power wiring issue.
Do you have actual grounded outlets with real safety ground wiring?
If safety ground pin of outlet is only connected to neural wire, then that ground level varies basing on how much outlet is loaded:
Returning current causes voltage loss in neutral wire.

Also could be some kind ground loop issue.
That's easy to distinguish from frequency. Sample here:
https://en.wikipedia.org/wiki/Ground_loop_(electricity)

 

[LuckyBenski]

Good point - your TV wont be grounded so will be getting grounds via (among other routes) any HDMI connections. So it may have ground loops around several audio devices.

You could try removing all connections to the TV other than your PC.