1 2 3 First Previous 258 Replies Latest reply on Jan 16, 2019 10:45 AM by camelx

    CF791 Freesync black screen via DP




      I received my new Samsung CF791 UW monitor this week but ran into some problems.

      When using ultimate mode on freesync with the display connected via DP the screen goes black/display port loses signal with the DisplayPort icon at the top left corner of the monitor when I start some games, for example Hellblade: Senua's Sacrifice and PUBG (both Unreal 4 engine games) seem to do this everytime, while Witcher 3 works OK so far. Every now and then ALT-tabbing with the affected games I do get into the game and after that it seems to work until I restart the game/computer.


      When I disable freesync or drop down to 2560x1080@100hz resolution it seems to work better and with limited testing there were no black screens.


      When using HDMI cable the black screen/signal loss does not happen but freesync flickers at the lower end of the range.'


      I've tested this issue with following drivers and it is present in all:






      I am using the cable and power adapter that came with the monitor.

      Computer Specs:

      • GPU: RX Vega 64
      • CPU+Mem: Ryzen 1700 + G.skill Flare X 3200mhz DDR4
      • MoBo: Asus Prime X370-Pro
      • PSU: Corsair RM750i


      Could this be an issue with the VEGA 64 GPU or the recent drivers that reportedly fixed the freesync flicker for this monitor?

        • 1. Re: CF791 Freesync black screen via DP

          I have the same monitor and Vega 64 GPU and experience the same issue. I'm not sure what the cause is here, but here's how you get around it. Once you do this trick once, you should not need to do it again unless you reinstall the drivers.


          Once you have installed the latest compatible driver and restarted your system:

          1. Download and install the Samsung CF792 latest driver here > http://www.samsung.com/us/support/owners/product/curved-monitor-cf791-series
          2. Start the games that give you a black screen.
          3. Once the black screen appears, press Alt+ Tab. This enables Windowed mode, you should get a picture.
          4. Navigate to the video menu, drop the resolution down to 1920x1080 Windowed mode, apply.
          5. Same again, but select full screen mode and apply.
          6. At this stage the screen may go black again, or it may work correctly from here on. It varies from game to game.
          7. Assuming it works okay, go ahead and Apply 3440x1440@100HZ. Quit the game normally, do not Alt+F4.
          8. If it does not work, apply 2560x1440 full screen. That should work, if it does repeat step 7 and quit the game.


          It's strange, but this works for me.

          • 2. Re: CF791 Freesync black screen via DP

            I had the same issue with Vega 64, DP 1.2a ACer XG270HU.   IT is the displayport!  change to HDMI 2.0 cable and the problem is gone!   I had the issues with Prey and Far Cry 4.  I really hope this solves both your issues. 

            • 3. Re: CF791 Freesync black screen via DP



              With some testing this work around seemed to work some games but not for all, PUBG seems to be very finicky with this, I have to do some more testing once I have time. But for now I have the most problems with PUBG and Hellblade: Senua's Sacrifice(which I got working for a while but after a restart I had to do the workaround again), which both are Unreal 4 engine games, this makes me wonder if it is a problem in the drivers.




              I tried HDMI 2.0 and it seems to work OK regarding the black screen issue, however with the HDMI 2.0 I do get the freesync flickering that has plagued this display and with DP I do not (when it works), so I would rather find a way to fix the DP issues if possible .


              For now I have ordered a new VESA certified DP1.2 cable from Accell to see if replacing the cable could work, because I noticed that when this black screen issue happens and I alt-tab, sometimes it gives the Display Link error, so hopefully replacing the cable could fix it.

              • 4. Re: CF791 Freesync black screen via DP

                I tried with a certified DP cable, same issues persists.


                It seems that same games work ok if launched in windowed mode and changed in game to fullscreen mode, however I need to do this every startup otherwise I get the signal loss issues, for now I am mostly able to work around this issue.


                Hopefully it is just a software issue and we do get a driver fix.

                • 5. Re: CF791 Freesync black screen via DP

                  I have same issue but i m using fury nitro.My simple solution for you is to try using freesync windmill demo before you start games and you wont get black screen anymore.However some games are unfixable at the moment like Senua and Mass Effect:Andromeda.Well, you can play it with Freesync disabled.The problem happened when they introduced 17.7.2 although even before black screen happened but not really often.Now there is no flickering , but Freesync causes black screen and doesnt really work correctly because tearing is quite obvious sometimes.



                  amdmatt@ does Amd know about this issue? How hard is it to test this, especially when they offered bundles with vega and cf791?!It must be something wrong with freesync because when it's disabled all problems dissapear with black screen. It is frustrating to have problems like this when you pay alot for top products.

                  • 6. Re: CF791 Freesync black screen via DP

                    Yes Fury X and acer 144hz XG270HU screen, the issue is HUGE with 17.7.2 and less affecting with 17.4.3.

                    I cannot use anything other than DP since the HDMI1 of fury doesn't support freesync

                    • 7. Re: CF791 Freesync black screen via DP

                      I have raised a ticket with our engineering department to try and reproduce the issue, for now use the workaround i posted.


                      Although it is not ideal, it has so far worked in every game i have tested.

                      • 8. Re: CF791 Freesync black screen via DP

                        Thanks, the workaround worked, at least in battlefield one for me


                        • 9. Re: CF791 Freesync black screen via DP

                          Same problem here with allmost the same setup (1700x, tridentz 3200mhz cl14, asus prime x370-pro, corsair ax860, Vega 64 liquid and cf791.)


                          I got mass effect andromeda working by turning monitor off and back on again, but there are some flicker after that and havent played for more then 15min, but with freesync on the monitor would turn it self off and on every 5sec

                          When spending over 3000€ on your pc you dont think there would be problems like this


                          Using samsung c34f791 with the ultimate engine (tried standard, but problem was the same) and dp-cable is the one that came with the monitor.


                          First the flicker and now less flicker, but with black screens/monitor turning itself off...


                          If i knew i cant use freesync with this monitor and the best amd card then i would have gotten 1080ti+g-syng for the same price becourse vegas prices...

                          • 10. Re: CF791 Freesync black screen via DP

                            maybe will be fixed, it's in patch notes in the new drivers:



                            Known Issues

                            • A limited number of displays may exhibit brief signal loss periodically.
                            1 of 1 people found this helpful
                            • 11. Re: CF791 Freesync black screen via DP

                              You heard back from them on this? Black screen on my R9 Nano with the same monitor as well.

                              • 12. Re: CF791 Freesync black screen via DP

                                No update yet folks, sorry.


                                Another workaround is to use a HDMI connection. This monitor supports FreeSync over DP and HDMI.

                                • 13. Re: CF791 Freesync black screen via DP

                                  Little update, the workaround don't work on latest drivers, many signal losses even in windows with 17.11.1

                                  (Workaround works in 17.7.2 not so well after)

                                  • 14. Re: CF791 Freesync black screen via DP

                                    It still works for me.


                                    Here's the exact steps i take.


                                    1. Start up game, black screen. Press Alt Tab.

                                    2. Navigate to the video menu, use a lower resolution and set it to full screen mode.

                                    3. Black screen, press Alt Tab.

                                    4. Repeat step 2, no black screen this time.

                                    5. Repeat step 2 but set 3440x1440, save and exit game.

                                    6. Issue resolved until i reinstall driver, driver crashes, or i enable/disable HBCC.

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