6 Replies Latest reply on Sep 9, 2016 12:05 PM by snapperorgan

    Abysmal OpenGL performance (RX480)


      Performance in OpenGL is worse than with my old GTS250. How can this be? It's especially annoying as I'm a developer working on an opengl based game.


      • Sapphire RX480 4GB
      • Windows 7
      • Latest Drivers
      • Asus P8H67-M PRO
      • INtel Core i5-2400
      • 450w power supply
      • 12GB ram
        • Re: Abysmal OpenGL performance (RX480)

          I am gamedev too.


          1. Are you using completely standard OpenGL? (no nVidia-only extensions at least) and what version of OpenGL are you using?


          2. Doom had terrible performance issues on AMD cards, seemly it could use OpenGL 4.5 on nVidia cards but only 4.3 on AMD cards... AMD made a driver patch that improved it, but not completely fixed it.


          3. Seemly Vulkan performance on AMD is worse than on nVidia too.


          4. On Linux AMD OpenGL performance is TERRIBLE, although much improved (seemly about twice as fast as 2 years ago), for some games you see Fury slower than GTX 960 on low resolutions. (see Phoronix to see benchmarks).


          5. All that, doesn't mean that you don't have a problem, maybe you actually do (or rather, the card or the driver has a bug). But AMD OGL performance has been historically bad, John Carmack commented a lot about it (and sadly people just told he is nVidia Fanboy and ignored him, instead of fixing OGL performance).

          1 of 1 people found this helpful
            • Re: Abysmal OpenGL performance (RX480)

              Thanks for your reply.

              We're using quite an old version of OpenGL with some extensions (only to ensure compatibility with older hardware).

              However performance is bad on other games that use newer OpenGL versions too.

              "AMD OGL performance has been historically bad"

              I didn't know this... So does that mean I should discourage our customers from buying AMD cards? I guess I am stuck with crappy framerates on my work pc for as long as I own this card, which is a sad thing.

              I didn't know I was posting to the developer forum either. Is there anyone from AMD here that can offer some tech support? Or do I need to go somewhere else?

                • Re: Abysmal OpenGL performance (RX480)

                  Seemly the post was moved actually. (I saw it originally on the support forums, or at least it is what I remember).


                  As for what to do, it is a very good question... AMD is trying to fix their stuff, but I dunno...


                  Encouraging nVidia sounds like a bad idea, considering their practices, but in the end what matters is if gamers can game or not, and if nVidia is needed, sometimes this is what you need to tell them.


                  As for why nVidia works better with OpenGL: during OpenGL early times, nVidia liked OpenGL so much, that they used the OGL standard as a "checklist" of features to put in their GPU, the earlier nVidia GPUs literally implemented OpenGL, with nVidia drivers kinda needed to "translate" DirectX calls to OpenGL, while AMD went the other way (giving more attention to DirectX, and OpenGL being the "foreign" API).


                  After the invention of shaders and all that stuff, this became less pronounced, but when you use OpenGL fixed pipeline, it shows, as nVidia cards implement OpenGL fixed pipeline in the hardware in a literal manner, while AMD cards don't do that.

                  1 of 1 people found this helpful
              • Re: Abysmal OpenGL performance (RX480)

                This doesn't sound right. The AMD OpenGL drivers do tend to be a bit slower than Nvidia GL drivers on equivalent hardware (hitting CPU bottlenecks sooner because of more correct/complete compliance checking) but I wouldn't expect anything like GTS 250 performance.


                Can you run some publicly available app (maybe new Doom ?) on both cards to make sure it's nothing specific to your app ?

                • Re: Abysmal OpenGL performance (RX480)

                  If you could provide source code access to the project you are developing, we would definitely want to have a look.