Asrock Fatal1ty Z170 Gaming Itx/ac HDMI 2.0 and Coil Noise Issue

[Damiko]

Build Specs :
Model Name: Z170 Gaming-ITX/ac
OS: Windows 10 Pro ,Build 10586 ,64-bit
Processor Type: Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz
Frequency: 4008MHz
DDR4_A1: 8192MB 1066MHz (DDR4 2133 ) 15-15-15-36
DDR4_B1: 8192MB 1066MHz (DDR4 2133 ) 15-15-15-36

HDMI 2.0 4Kx2k 60HZ NOT Working and sometimes random lost of Display signal during BOOT and LOGIN
I am using LG 27UD88-W 4K monitor with 2 HDMI 2.0 ports.
I am using HDMI cables provided by LG and also tried Amazon Basics HDMI 2.0 4K but still the same issue.

I tried all the instructions from the multiple forums,

1. Downgrading BIOS from 2.30 to 1.50 version
2. Downgrading VGA driver from 4331 to 4300 version
3. Did the \HDMIFwUpgrader\BobcatAuxISPTool_V2.05 tool and after upgrade it says ISP upgrade successful.

But it is still NOT working.

My motherboard got replace from that day to try it, but still doesn't work.

I also called service center to check the status, but instead I was instructed to try the CUSTOM Display resolution at the Graphics properties, but still doesn't work. I can use Display Port to get it work but I also want the HDMI 2.0 to be working when I want to use 2 4k monitor.

And another thing I notice after that custom resolution setup, NOW it is having COIL WHINE(NOISE) when it is displayed at 4k/30hz resolution. I have reinstalled the Windows, graphics drivers and bios firmware to troubleshoot but no luck. I have to lower it down to 1080 just to remove the noise.

Is the motherboard defective? I am not hearing any coil noise before with my old mobo.

What else could I do here?
This is a common issue using HDMI 2.0 with this motherboard and still ASROCK do not have clear instruction how to fix this. Its quite frustrating

 

[Lutfij]

1| You could return/RMA the board on grounds that the board is faulty but your specs list is half staed. Please list your full system's specs as:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
OS:
Case:

2| Are you sure the coil whine comes from your board and not any other component, like the PSU?

3| If this is known to happen on the same board by other users then it's best if you returned it and got a board from another manufacturer provided BIOS updates haven't helped at all.