Running Two Monitors with Different Refresh Rates & Resolutions

I have the two Ozb monitor favourites, the Dell S2721DGF ([email protected]) and S2721QS ([email protected]) connected to the same PC. For some reason, the monitors switch to lower refresh rates when I do this (165Hz turns to maybe 60-70Hz and 60Hz turns to around 40-50Hz) and makes the PC quite unresponsive sometimes. Sometimes there are weird artefacts when scrolling, and UFO test is unable to sync at all, or there are 11+ stutters (it seems it wants to push to 165fps but fluctuates between 140-155fps). However, there are no issues running them separately, or running the monitors at 120Hz and 60Hz respectively. How can I make these monitors run properly?


  • +1

    That's strange. Windows 10 normally handles 2 different refresh rates pretty well after the 20H1 update.

    Which graphics card have you got? Is it on the latest driver?

    • Yeah, I have the 3070 with latest Nvidia drivers and I have the latest version of Windows as well

      • Is it only while gaming or just normal basic activities?

        • Even just scrolling on Chrome is noticeably choppier on the 4K monitor when the other monitor is set to 165Hz, not sure if it's some sort of vsync/gsync setting that's messing it up

          • @Could Be Better: Try this Reddit solution

            go to your nvidia control panel and click on adjust desktop size and resolution.Set both your monitors to "Perform Scaling on" to your GPU and not the display which is the default.



            Go to your settings in chrome and click on advanced options at the bottom and disable hardware acceleration.

            If that doesn't work, as below I would delete all drivers and start again. Which CPU have you got?

            • @MS Paint: Ok not sure if this helps, but here’s a comparison:

              My scaling is for both monitors is set to GPU and turning off HA in Chrome makes the problem worse (as seen in the videos)

              I guess I’ll have to delete the drivers and start again, sigh… I have a 5600X

              • +1

                @Could Be Better: I've found the problem. You are reading The Age.😀

                That's pretty annoying.

                Delete all drivers and start fresh.

                • +1

                  @MS Paint: Happens to all the other sites as well, I should’ve used Ozbargain but this wasn’t exclusive to The Age haha

                  Yeah, I’m gonna start that now, thanks for your time and help

  • +1

    No idea myself but curious about this cause I have a S2721DGF on the way for a dual monitor setup (smaller 1080p60 next to it vertically) and might run into this sort of thing.

    What GPU? Tried cleaning the drivers with DDU and starting again with different versions? Someone will ask so it might as well be me, though the fact you're doing UFO test and stuff kinda implies you would have already done the basic stuff

    • Nah I think it's just me and my crappy luck, I'll have to reinstall the drivers and hope everything works alright. I have the 3070

    • I have an S2721DGF sitting next to a U2412 and do not have this problem.

  • +1

    First make sure your PC OS is the latest version and has the latest driver for the graphics card(s) you have.

    If this does not help then look at the resources to see if the PC is constrained somewhere. You can use top on Linux to show the process's running.

    • Here is a comparison of the jitteriness on the 4K monitor depending on the refresh rate of the other monitor:

      I have the latest drivers and updates, so not sure what’s up with this..

  • That's really odd, I am running S2721DGF [email protected] and an old Samsung IPS [email protected] perfectly fine.

    I hope you find the fix to this OP.

    As a suggestion maybe try switching the display connectors around on the GPU, maybe one of the plugs is bad possibly?

  • I had this issue for years.

    I have a 144hz Dell S2716DG and a 60hz Dell P2412H.

    As you described scrolling chrome on one screen will cause videos in the other screen to lag. Or even just moving my mouse around quickly. It manifests itself in all sorts of weird ways. UFO test is an easy way to detect it.

    I tried every possible fix online to no avail (even the 120/60 fix didnt work for me)

    Eventually just had to disable my secondary monitor every time i played a game as it would cause lag/stutters in game.

    BUT, recently it finally fixed itself. I dont know what it was. I recently had to reinstall windows from scratch when i upgraded my cpu/mobo. I went from an i5-4690k to a R5-5600x. GPU didnt change (still an RTX 2080). It's a fresh install so I havent gone through and edited any settings. But its fixed.

    Edit: if you said the 120/60 trick worked for you, maybe try overclocking your 60hz one to 72hz? The OC worked on my dell 60hz monitor (however didnt fix the lag).