High DX11 CPU overhead, very low performance.

Discussion in 'Videocards - AMD Radeon Drivers Section' started by PrMinisterGR, May 4, 2015.

  1. aliindrawan

    aliindrawan New Member

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    Do you mean that my i3 will run out of compute performance first before driver/DX command?

    Sorry, that was a bit too technical for me :3eyes:
     
  2. Fox2232

    Fox2232 Ancient Guru

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    AMD DX11 driver is single threaded, so it can't take advantage of multi core CPU.

    But games themselves are more often multi threaded these days than in past even in DX11 games.
    You have main thread which calls out and dispatches tasks, moves data around (like inputs from mouse/keyboard).
    And each of those things it deals with may be part of another thread (or more).

    Your biggest enemy is CPU based physics, or over-complicated AI running on too many instances (character/unit).

    In general fps games, you'll likely to be safe for quite a few years as they tend to be pretty simple.
     
  3. aliindrawan

    aliindrawan New Member

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    I think I'll be safe since I'm not into RTS / 4X games. I imagine running racing games / sims will be tough.

    Thanks for this :thumbup::thumbup::thumbup:
     
  4. Krteq

    Krteq Master Guru

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    WTF? Nope.

    Try process explorer and you will see :rolleyes:

    Anyway, AMD driver supports DX11 multi-threading, but there is missing support of optional feature - command lists.
     

  5. aufkrawall2

    aufkrawall2 Master Guru

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    I think the last game where the CPU overhead was a problem with AMD was Rise of the Tomb Raider, but it got a DX12 patch.
    Other open world/level games like Mirror's Edge or Witcher 3 DLC are running fine. AMD doesn't have overhead problems in every game.
     
  6. Fox2232

    Fox2232 Ancient Guru

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    Just because single thread jumps all around place, it does not make it multi threaded.
    It is very badly occluded thing to see through task manager/process explorer.
    AMD's driver as practically any software created and destroys threads.
    But for its most important things driver does not spring dozens of threads.
    It even chokes if it gets spammed.

    That's why DX11 API draw calls test in 3DMark has lower multi threaded performance than single threaded on AMD's driver and DX11.
     
  7. The Mac

    The Mac Ancient Guru

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    thats not how it works.

    the driver itself is multithreaded, however there is only one submission queue.

    The "single threaded" comes from the fact that there is only a single thread for submissions.

    You can have as many threads as you want gathering up info and calculating stuff, but it all has to get funneled into that single submission thread.

    This is a DX11 limitation, its applicable for both AMD and Nvidia.

    Command lists are a DX11 option that must be explicitly implemented by the game itself. It was supposed to decrease submission latency to the queue and speed up submissions. It is NOT a DX performance tweak that universally give performance gains. To my knowledge Civ5 was the only game to actually use it.

    AMD experimented with command lists, however they determined there was a negative impact on performance for their architecture and chose not to implement the option.
     
    Last edited: Jun 24, 2016
  8. chumanga1

    chumanga1 Member Guru

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    An update for those interested, i tested BF4 again in same 64 map but new driver feature Power efficiency disabled. Yet this time i choose lowest quality of the game to release 770 GPU power limitations. This time i7 HT enabled.
    Tested in GTA 5 too.

    Bf4
    https://youtu.be/XoKu0_2ozAc

    GTA 5 with 2 distinct quality settings and CPU(4vs8Thread) comparison:
    https://youtu.be/S546TL2LWNY
     
  9. xacid0

    xacid0 Master Guru

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    ^ Great video, too bad you didn't tested 4c/8t on the 770 in GTA5.
     
  10. aufkrawall2

    aufkrawall2 Master Guru

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    I really wouldn't be surprised if BF1 had lower CPU requirements than BF4 (both DX11).
     

  11. Agonist

    Agonist Ancient Guru

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    Id be shocked to see BF1 DX11 tbh at launch.

    But BF4 uses DX11.1 which does help with Direct X 11 single threading.
     
  12. aufkrawall2

    aufkrawall2 Master Guru

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    Yeah, but it's still far more CPU limited than Battlefront. Maybe one can't compare them to 100%, but I think it's obvious that BF already has some overhead or multithreading optimizations that BF4 didn't have.
     
  13. Szaby59

    Szaby59 Active Member

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    But Battlefront also has much smaller game modes: 40 vs 64 in the largest game mode.
     
  14. aufkrawall2

    aufkrawall2 Master Guru

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    That's why I said you can't compare them by 100%.
    But Shanghai with 40 players will most likely still be slower by a noteworthy amount than walker assault on Hoth.
     
  15. Fox2232

    Fox2232 Ancient Guru

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    BF1 will likely support even Vulkan at launch.
     

  16. vase

    vase Ancient Guru

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    thats nice to hear. independently from any low-level improvements i liked VRAM management in openGL better. even in the new DOOM demo the scene changes are smooth as hell (pun intended or not, i dont know) with 2GB.
    not saying i have big problems in dx11, but it's a noticable difference.
     
  17. sammarbella

    sammarbella Ancient Guru

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    I would like to see BF1 with native Vulkan support not via wrapper like dota2...and compare performance Linux VS Windows.
     
  18. theoneofgod

    theoneofgod Ancient Guru

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    Don't jinx it now! :D
     
  19. aufkrawall2

    aufkrawall2 Master Guru

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    How is Mirror's Edge: Catalyst running for you guys?
    I'm having really nasty stutter and freezes. Having also nasty stutter on a GTX 1070 (quite less nasty than with the Radeon, but it still breaks sense of fluidity).
    Maybe it's crap iteration of Frostbite engine and it doesn't like my CPU/PCIe 2.0?

    I'm really disappointed by the graphics, btw. Looks like crap compared to early access Cryengine games like Wolcen or Kingdom Come, lots of prerendered videos with shabby compression, screen space reflections are really bad compared to The Division and so on and so forth...
     
  20. yasamoka

    yasamoka Ancient Guru

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    Wrapper? Do you know what a wrapper means...?
     

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