Flickering on borderless windowed G-SYNC mode

[Olddddd]

Hello guys,

Setup:

• Monitor: BenQ EW3270u

• Resolution: 4K, 60Hz

• Display mode: borderless windowed for gaming

• Display interface: DP 1.4

• GPU: RTX 2080Ti

• G-SYNC: On via NCP (monitor compatible, even though it's a FreeSync)

• Dual screen: Yes, Dell U3415W

For gaming content, I'm facing flickering with the setup mentioned above. If I play on fullscreen mode, the issue disappears, but I lose the Windows HDR (another issue I'm trying to fix).
Also, if I put a 30FPS limit, issue seems also to disappear (but can show from time to time).

I tried to extend the FreeSync range with CRU from 40-60 to 25-60 but doesn't change anything, unfortunately.

So currently, I'm trying to either:

-Fix the flickering on borderless windowed mode, to keep the Windows HDR on
or
-Fix the HDR that disabled when I switch on full-screen, like that I will only have to switch to full-screen mode to get rid of the flickering, if not fixable

And not that easy to fix. ^^

So far, the only fix I found for Windows HDR enabled on full-screen is this: https://answers.microsoft.com/en-us/win ... d31?auth=1 but I lose the G-SYNC.

Does anyone has faced this kind of issue?

Thanks.

EDIT: On 60FPS limit, the issue seems also to vanish, but everything in between (30-60), flickering comes back.

[Olddddd]

Well, so after many attempts to fix that, I discovered some things:

First of all, I don't need Windows HDR anymore, it's fucking up colors on some games, so fullscreen on every game.
Secondly, to fix the flicker on some games, I have to activate v-sync or fast v-sync (via NVDIA panel than the game's settings) and also lock the FPS. It worked on GTAV for instance but not on Witcher 3, what can I still try?