VR Performance CPU Bound?

Discussion in 'General Discussion' started by singhka, Sep 4, 2017.

  1. stonec

    stonec Member

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    Yeah it is, but I suspect it is due to graphics drivers distributing load to free cores, DX11 is quite good at this. The bottleneck will still appear for a single core, as long as rF2 main threads (physics+graphics) aren't multi-threaded more. I can't comment more on VR CPU usage because I don't own a headset, so it's just based on what I heard and read. For non VR CPU makes absolutely no difference in rF2 unless you add lots of AI, that I have confirmed myself. I even saw a test where some guy had underclocked his i5 to 1.5 GHz and it made no difference on FPS in rF2.
     
    Last edited: Sep 6, 2017
  2. Andregee

    Andregee Registered

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    What i meant is that a 7700k is faster in rf2 than a 3770k, because the CPU generates more instructions per clock, nearly about 25% more, the 4770k only 10%. Many 7700k reaches 5ghz, but the most of 3770k or 4770k not.
    So if you want the highest available framerate in rFactor2, you will have to use a 7700k. I am using an 3770k

    Look at the left upper corner
    1.
    3700mhz 2 cores (limited with task manager)
    https://1drv.ms/i/s!AuYcx2IKUBpJ9yG5qj628FNoEx0R

    2.
    3700mhz 4 cores
    https://1drv.ms/i/s!AuYcx2IKUBpJ9yAlSoZNwKVdro4D

    3.
    4600mhz 4 cores

    https://1drv.ms/i/s!AuYcx2IKUBpJ9x_q8mebzbbXZfdQ

    There is a fps gain from changing from 2 to 4 cores, not as much as expected, because the multicore scaling is not very good, but rFactor2 is not generally limited to 2 cores.
    Setting clock speed to an higher level , you will a performance increase too.
    All in all the the time the performance is CPU limited, its allways a CPU limit when the GPU usage is noticeable below 100% or what do think will limit the framerate while the GPU is not at the limit.
    Like i said, comparing 4 or 6 core CPU with nearly the same per core performance does not show a cpu limit when the games uses only 4 core or less.
     
    Last edited: Sep 6, 2017
  3. Ari Antero

    Ari Antero Registered

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    So your claim is that I7-7700k is outperforming I7-5960x at 5.0 ghz ?
     
  4. The Iron Wolf

    The Iron Wolf Registered

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    I tested 3.2/3.8/4.6 Ghz with Sandy Bridge E. FPS increase is linear in my case (60/72/90FPS). Note this is not a VR test, but stilll. Of course, there are many things involved, but at least on my system GPU load is low (1080ti) and AA does not reduce performance, which is usually an indication of CPU limit.

    The fact that 7700K is not giving much of a boost is concerning, but not surprising considering by how much IPC increases nowadays.
     
  5. The Iron Wolf

    The Iron Wolf Registered

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    Note that nvidia driver is multithreaded, so even though game looks like primarily two threaded, the fact that there's some boost from 2 additional cores is not surprising.

    Note that all of this is just speculations, only developers know what's going on for sure :)
     
  6. Andregee

    Andregee Registered

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    If the 5960x doesn´t reach 5ghz, yes and even with the same clock, the 7700k has around 10% more IPC.
     
  7. Andregee

    Andregee Registered

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    I used an AMD card for a long time and i noticed an performance increase from changing from 2 to 4 cores too.
     
  8. Comante

    Comante Registered

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    Question, not for VR, but maybe who knows, related. Yesterday I changed my GPU, so I was able to up my graphic setting in RF2. What I noticed, apart much more FPS because the new card is overwhelmingly more powerful than the older one, is that CPU usage seems to be increased. I checked with window system manager, and of my 4 core, 2 are somewhat 75/80% used. The purple bar before the upgrade was sensibly lower in game.
    So do the graphic detail add load to the CPU other than the GPU ? This could be a reason why VR seem dependent on CPU limits...
     
  9. Ari Antero

    Ari Antero Registered

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    I7 5960x which I have has 8 Cores and 16 threads cooled by VapoChill LightSpeed and it is stabil at 5,0 ghz. If I run at 3,5, 4,4 or 5,0 ghz. I don`t have any fps increase with high clock speeds. Let`s just hope that next update will solve all the unanswered questions regarding VR performance CPU bound :)
     
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  10. singhka

    singhka Registered

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    just saw that the 8700k is due in october, looks like there's a decent jump in ipc/performance per clock compared to kaby lake, and not only that, the the cpu is 6 cores 12 threads from the old 4/8 all at the same tdp of 95w, so looks like best of both worlds. also they updated turbo boost system - now has max clock speeds multiple core load scenarios for single core, 2 core, 4 core and 6 core depending on the load so will def help make the most and scale better depending on workloads compared to older architecture, hopefully this translates to rf2, lucky i didnt waste my money into x299 platform.
     
  11. Adrianstealth

    Adrianstealth Registered

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    Going to pick one of these up for mobo mem cpu upgrade

    Wonder if another flurry of rfactor2 optimisations will come soon ?
     
  12. Andreas Morewood-Myrvang

    Andreas Morewood-Myrvang Registered

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    I dint think it's CPU bound. I do Vr with i3 7100,16gb .but with a 1080ti. Full graphics. Of course with a lap against 20 other cars,the CPU will struggle but just put down the settingd
     
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  13. Ari Antero

    Ari Antero Registered

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