Question Asus VG27A flicker

[Seladon]

I built my PC this week, all the parts are new, except from my second monitor which is an LG 23EA53 (1080p 60Hz). From the beggining, on my new Asus monitor, part of the screen (not always the same part though) has been flickering white, black or grey, maybe once every 15 minutes, sometimes even less often. Today I did some testing on that and managed to find a way to make the issue appear more often. I made a video of the problem happening where I scroll up and down on a white page with black dots. It made the issue appear a lot more often (every few seconds as you might be able to see). In the video, I'm running the monitor at 165Hz with Gsync enabled and my other 1080p 60Hz monitor connected.

Spoiler: My setup

PCPartPicker Part List

CPU: AMD Ryzen 7 3700X 3.6 GHz 8-Core Processor ($399.99 @ Amazon Canada)
Motherboard: Asus TUF GAMING X570-PLUS (WI-FI) ATX AM4 Motherboard ($244.99 @ Newegg Canada)
Memory: Corsair Vengeance LPX 16 GB (2 x 8 GB) DDR4-3200 Memory ($102.99 @ Amazon Canada)
Storage: Samsung 860 QVO 2 TB 2.5" Solid State Drive ($239.99 @ Amazon Canada)
Storage: Seagate Barracuda Compute 2 TB 3.5" 7200RPM Internal Hard Drive ($64.99 @ Newegg Canada)
Video Card: Gigabyte GeForce RTX 2070 SUPER 8 GB WINDFORCE OC 3X Video Card ($667.99 @ Amazon Canada)
Case: Fractal Design Meshify C ATX Mid Tower Case ($135.01 @ Amazon Canada)
Power Supply: Corsair RM (2019) 850 W 80+ Gold Certified Fully Modular ATX Power Supply ($149.99 @ Amazon Canada)
Monitor: Asus TUF Gaming VG27AQ 27.0" 2560x1440 165 Hz Monitor ($549.99 @ Amazon Canada)
Total: $2555.93
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2020-02-16 18:51 EST-0500

I tried a few things to isolate the problem, although I wasn't able to change actual parts in the PC :

1. Replacing the display port cable didn't change anything.
2. Lowering the refresh rate to 144Hz or 120Hz didn't change anything.
3. Deactivating g-sync didn't change anything.
4. Unplugging the second monitor didn't change anything.
5. The issue doesn't happen when running only the LG (1080p) monitor.
6. The issue doesn't happen either on the Asus if I set it at 60Hz, even if G-sync is turned on.

Any idea what could be causing this and how I could fix it ?

 

[Oussebon]

Does disabling ELMB sync have any effect?

 

[Seladon]

I made a few more tests.
Disabling HDR doesn't fix the issue.
Disabling ELMB sync doesn't fix the issue.
The issue seems to get worse when I leave monitor and PC on for a long period of time.

 

[evyosh]

I have 3 Different Displays. One ASUS VG278QR 165Hz, LG 24gm77 144Hz my old gaming monitor and an IPS 60Hz Philips and they all have a flicker when you scroll up and down. I don't think this is a problem.