5 Replies Latest reply on Aug 11, 2017 4:10 PM by chrisredfieldjr

    Does enhanced sync work with crossfire?


      The question is this: will enhanced sync work with crossfire? Currently I noticed that it does not work with crossfire. I have a RX 580 + RX 480 in crossfire. Are there plans to put it compatible with multi gpu?

        • Re: Does enhanced sync work with crossfire?

          By testing, I discovered that enhanced sync does not work with crossfire. Always tearing occurs. Any plans to implement enchanced sync with crossfire?

              • Re: Does enhanced sync work with crossfire?



                I am assuming you are not using a FreeSync Monitor.


                I  do not have an RX580/480 and unfortunately Radeon Crimson ReLive 17.2.2 does not support Enhanced Sync yet.
                I cannot run Enhanced Sync to test it out for you yet.
                Please bear with me though ...


                I was testing Radeon Chill in Crossfire with FreeSync on using  "The Witcher 3: Wild Hunt" just recently with a pair of R9 Nano (Fury X) cards running on i7-4790K system.
                My FreeSync Monitor is a 'cheap' 22 inch Viewsonic Monitor which I purchased to try out FreeSync.
                I has a display frequency range of 47-75 Hz at 1080p which drops to 47-60Hz at 4K.


                My R9 Nanos in Crossfire can output around 110-120 FPS in The Witcher 3: Wild Hunt  with all graphics settings maxed out on Ultra.
                In this case, my GPU's in Crossfire can output frames much faster (~ 110FPS) than the 75 Hz refresh rate of the monitor, so I get some scrolling screen tearing in this case.


                So I normally set Frame Rate Target Control to 75FPS as well, even  when using a  FreeSync Monitor, so eliminate screen tearing in this case.
                Lack of tearing and steady GPU output at 75 FPS synchronised to the monitor output refresh rate is more important to me than faster response time with screen tearing.

                If the FPS ever does dip down below 75 briefly , say 65 FPS then the FreeSync seems to keep the image steady and I see no stutter because the lower end of the FreeSync range is 47 Hz on my FreeSync Monitor, and my GPU's in Crossfire are powerful enough to prevent that problem.


                From my limited understanding of Enhanced Sync (*I have not seen any detailed explanations of exactly what it does yet ... )  I think it:


                1. Delivers uncapped Frame Rate to the Monitor to decrease latency when the GPU output  is faster than the Monitor's refresh rate.  (= Minimize latency still but some tearing...)
                - I do not know for sure if it is like Nvidia Adaptive Sync or if they have also implemented a "Last Rendered Frame Buffer" similar to Nvidia Fast Sync.


                2. Disables Vsync when GPU output is lower than the Monitor's refresh rate it turns off Vsync, to minimize stuttering.


                I would try turn on Enhanced Sync, with Frame Pacing on first. 
                If that does not work I would then set Frame Rate Target Control to match the Monitor Refresh Rate, at least in that case you still get some benefit from Enhanced Sync if output FPS drops below the monitor refresh rate.


                Here are some references on Enhanced Sync and FreeSync.

                AMD Introduces 'Enhanced Sync' Framerate Synchronization Technology

                Everything you always wanted to know about FreeSync... - YouTube

                Since I read that AMD Enhanced Sync is a response to Nvidias Fast Sync, here is a detailed explanation to Nvidia Fast Sync.
                What is NVIDIA Fast Sync? - YouTube

                What is NVIDIA FastSync technology? - YouTube


                And some comments about issues seen.


                If you have read the above and still come to the conclusion that nothing helps then maybe submit an AMD Report Form here: AMD Issue Reporting Form

                Hope this helps in some way.



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            • Re: Does enhanced sync work with crossfire?

              At this time, Enhanced Sync is not compatible with CrossFire, Vulkan or OpenGL.

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