Custom Resolution Utility (CRU)

[wild0077]

Hello there, everyone.

I own an LG 29WK600 (29" UWD 2560x1080 75Hz "HDR"), and am currently using it with an RTX2080S through DisplayPort (1.2 I believe, GPU-Z shows 5,4Gbps). Some time ago I was experimenting with nVidia custom resolution, typed in 3440x1440 just for the kicks and for my surprise it "worked", I mean, the image came right up, stuff on the screen were smaller, and no glitches that I could see. Typed in 3840x1600, and it also worked, same way described before, both at 75Hz. For some reason the image became a lot darker when using custom resolutions through nvidia panel, but at least I knew it might be possible.

After that, I decided to try CRU and see if I could create new resolutions properly, and I could, this time I went only for 3840x1600 75Hz, everything worked fine, the OSD from the monitor itself showed that resolution. However, from time to time the screen goes black for like 1 second, and than comes back. Happens at 3440x1440 75Hz as well, everything seems to work beautifully, and then out of the blue screen flashes black and comes back.

Naturally I tried lowering refresh rate, and both resolutions work flawlessly at 60Hz, no flashes at all, but since the monitor is rated 75Hz, I was hoping to actually be able to use those resolutions at the "desired" refresh rate.

What I would like to know, please, is if there is any possibility that the "flashing behavior" is something that can be solved by messing around with the settings on CRU? Or it sure means that the monitor simply cannot handle 75Hz at those resolutions?

I'll attach a few images from my current settings, I've been messing around with timings for a while now, with no luck, but the weird thing for me is that the flashing has no pattern at all, sometimes it occurs watching videos, sometimes does not, sometimes I can play a game for almost an hour without any issue, sometimes it's just impossible. I lowered the FreeSync range from 40-75 to 48-75, to see if it could help, but no deal. Also, since I could not find something specific about my case when searching for clues, I've added HDMI and HDMI 2.0 blocks, but I have no idea if it makes any difference or not in this scenario.

Thank you in advance.