I just installed my new RTX 3080 FTW Ultra I bought on Wednesday.  So far everything went fine except IO am getting a half a screen flicker on my 3rd monitor.
 
I have all three 1440p monitors plugged in via Display Port.  Two, including the one with the flicker, are 60 Hz panels, nothing fancy.  The last one is a Gsync 144 hz monitor.  When all three are connected via Display port, the last DP plugged in (top to bottom of the card) flickers.  It doesn't matter which monitor I put in there.  I set the Gsync to 144 hz, the same issue, I did not try 60 Hz.
 
The monitors all worked fine on my 2 1080 Ti's I had in before, and the RX 750 I had in for a short period today before I installed this new card.
 
IT appears other folks are having the same issue:
 
https://forums.tomshardware.com/threads/rtx-3080-flickering-on-top-of-screen-using-dp.3650406/page-2?view=date
 
As of now I am using HDMI on that last monitor and it is working fine, but I need that HDMI for my VR headset. 

I disabled Gsync, the issue is still here.
 
 I tried multiple cables (I have more DP cables that I could want) and all had this issue.  I used the same cables and monitors with 2 other GPU's (1080ti and a RX570) and did not have an issue. It's only with the 3080. 

I disabled Gsync, the issue is still here.
I tried multiple cables (I have more DP cables that I could want) and all had this issue. I used the same cables and monitors with 2 other GPU's (1080ti and a RX570) and did not have an issue. It's only with the 3080.
 
Here is a video of the issue, this is on my PC:
 
https://youtu.be/3ZG9u_mvl5o

I had this issue with my 3080 using 2 monitors. Both are 120hz and gysync. I have gysync on, set to fullscreen.
I fixed the issue by disabling the Geforce Experience in game overlay.

I was able to get the color options to show up but setting it to limited made no difference.

I don’t have an option to go lower than 59 hz

I have the same or similar issue with my EVGA 3080 FTW3. This issue does not present on my old 2080 Ti nor a 2060 Super so it does seem to be an issue with 30 series cards.

I have an LG 27GN950-B 4K 144hz GSync compatible (certified) monitor and a 24” 1080p 144hz IPS monitor that is not certified but works with Gsync compatible. Either way the 1080p has been tested both Gsync on and off.

The 1080p monitor is setup in portrait like OP and I also get that weird halfway screen flicker and worse on my screens. My secondary portrait will do the half way crazy flickers. My primary 27” 4K will flicker on and off.

I discovered a temporary fix was to change the refresh rate of my secondary screen to 120hz. After doing this everything works. Not a real fox but a temporary work around that works 100% until Nvidia or EVGA fix the issue.

Sounds like that one dp port is defective.

Apparently Windows was setting the refresh rate of the offending monitor to one of the 'interlaced' versions. In the windows advanced settings for the monitor I dropped it back to the non-interlaced version and it worked. Same net effect as the NVIDIA control panel solution above, just clears out any strange refresh rate settings set by other programs

Sounds like junk adapters now.

sometimes bad dport cable will do that, it  happen to me before until I replace the cable.

Zvedza
Could be bad cable, just look at my thread to see what those or a bad DP port can do.

I did however notice when trying to fix my issue was that in windows advanced display settings (or something like that) my refresh was half of what i set in my Nvidia control panel. Knowing our luck with these cards it probably wont help, but figured on the off chance it could fix it you could check to see if thats the case. 

I thought that too, but used the same cables on a 1080ti, and a 5600XT and they work fine with the same monitors. 

Jstandaert

schmak01

Zvedza
Could be bad cable, just look at my thread to see what those or a bad DP port can do.

I did however notice when trying to fix my issue was that in windows advanced display settings (or something like that) my refresh was half of what i set in my Nvidia control panel. Knowing our luck with these cards it probably wont help, but figured on the off chance it could fix it you could check to see if thats the case. 

I thought that too, but used the same cables on a 1080ti, and a 5600XT and they work fine with the same monitors. 

I had the same issue in a way. when I would plug my OLED in I would get screen flicker. come to find out not all cables are created equal. It would make sense that your 1080 and 5600 work because those are lower performing cards dp 1.4. where as 30 series has 1.4a. what happens if you use a HDMI cable that supports 8k? having that 48GBs of bandwith will tell you if you have a bottleneck or not. currently, with HDMI 2.1 it outperforms DP. I personally think it sounds like you have a signal transmit issue. either in the card I/O or you are using sub par cables.

These are older monitors, not sure they can support DP 1.4, more or less A. They are 1.2 ports, and I don't see a way in the nVidia control panel to force 1.2. 
 
Monitor info:
 
PB278Q | Monitors | ASUS USA

I stated earlier I don't have an issue over HDMI, using Non-2.0 HDMI cables and a DP to HDMI adapter. 
 
This is strictly a DP issue.  
 
Although it is "backward compatible" if the card is trying to force 1.4 features to 1.2 monitors and they are interpreting it wrong, it could be an issue. The cables are 1.2 cables. 

Well the fix for me is running both at 58 Hz. No issues when I do that.  It's not worth RMA'ing the card or using the DP to HDMI adapters since that just introduces another point of failure and honestly, U have everything very cable managed in my desk, running new 15ft HDMI cables will be a pain.  I'm good with the 58hz, can't really notice the difference between that and 60 and it doesn't seem to impact my 144hz gsync monitor at all. 
 
I might try a 1.4a cable later if I have the need to buy one, but for now using DP 1.2 and 58 Hz seems to be the most stable.