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Capping FPS Question

Discussion in 'Assetto Corsa' started by bsmooth, May 16, 2019 at 15:35.

  1. bsmooth

    bsmooth

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    I must say after installing Content Manager and using the new shaders AC looks great, but I must have a system thats on the edge as far as performance goes, although I get anywhere from low 90's to 120's for FPS. I noticed though I've been getting some micro stutters when theres a lot of cars visible.
    Would capping my FPS help this, and how do you go about doing it ?
     
  2. RasmusP

    RasmusP
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    I like the fps limiter of content manager :)
    Just put to the lower third of the fps you get. So maybe 97 or something.
    If you don't have freesync or gsync, you might see tearing though. You should see tearing without capping too but due to the fluctuating fps, the tearing border will move randomly and be less noticeable.
    Just try it :)

    For me there's not difference between the rtss limiter and the content manager limiter.
    I'm not sure if the standard launcher has a limiter option too, didn't use it in over 2 years...
     
  3. Rogerbee

    Rogerbee

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    I have an AMD FX processor and if you have VSync turned on the frame rate is capped anyway. I have to have it turned on because AC is a complete jittery mess without it. I got 75fps through DisplayPort, which I borked somehow, and get 60fps with HDMI. Thing is, it is really smooth and I can turn all the goodies in Custom Shaders Patch on and it is still nice. I got tearing with the Barcelona City circuit at night, but, that is really resource heavy and there are a lot of lights.
     
  4. Rogerbee

    Rogerbee

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    Ignore all of the above!

    The jittering and tearing that I was experiencing with VSync off was NOT due to it being off! It was caused by the Virtual Reality pre-rendered frames setting in NVidia Control panel! By default if is set to 1, I set it to 'Use the 3D application setting' and the jitter and tearing are gone and my frame rates are unlimited!!

    [​IMG]

    Having an FX processor had NOTHING to do with it!
     
  5. bsmooth

    bsmooth

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    Last night I looked into it and mine was not set to VSync at all. I set it and for most of the session I had flat lines on processor use with no spikes at all. In the last 15 minutes I did get the occoisional spike and micro stutter, ut I don't know why.
    definately worked better with Vsync on.
    Question If you have VSync on shouldn't the FPS be around 60 or slightly below all the time ?
     
  6. RasmusP

    RasmusP
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    Vsync will lock the fps to the Monitor's refresh rate. Depending on what that is, the fps will be different.
    However the fps can still go down, or spike a few fps above the refresh rate. That's normal!

    To really understand how this all works you have to look at "fps" as "from frame to frame timings".
    If you fps drop, you'll see a kinda big stutter. At least if you use the standard vsync and not fast, adaptive, etc.

    So the fluctuations might be like this:
    60 fps = 16.67ms from one frame to the next.
    Frame1 -> 16.67ms -> Frame2 -> 16.67ms etc.
    Now if the fps drop, it will be like this:
    Frame 1 -> 16.67ms -> Frame 2 -> 16.67ms, fps dropping -> Frame 2 again! -> 16.67ms -> Frame 3

    So between Frame 2 and 3 you'll have 33.34ms, resulting in a stutter. Now the thing is, that "fps" is often measured multiple times per second, which results in "estimated fps values", actually rather showing the "frametime average over the last measurment duration".
    So if the fps drop for a few frames, you'll see something like 58 fps and when the PC gets to keep up again, you'll see a slightly higher fps value than 60.

    I don't know why the performance gets worse after some time into the session. I guess it's down to the weather or time of day changing? Or maybe your apps show more than in the beginning? Leaderboard apps showing longer numbers for the gaps, More cars close to you or something?
     
  7. Rogerbee

    Rogerbee

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    Yes, that was what I had.
     
  8. Rogerbee

    Rogerbee

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    Hmm, sadly, on resource heavy tracks like LA Canyons, turning the VSync off caused too much strobing for my liking, so I had to turn it back on again. Still looks good though and it is lovely when it's smooth.

    Still, you may have different rigs to me and may get more mileage out of the settings than I can. Let me know...
     
  9. bsmooth

    bsmooth

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    Its weird around the Highlands track I get very smooth framerates with 16 cars ontrack, yet on the small loop of Circuit Mas du Clos I can get short stutters, which makes no sense since Highlands is so much bigger.
    This is my rig for those interested:
    MB ASROCK|P67 EXTREME4 (B3) P67

    EVGA GeForce GTX 1050 Ti SC GAMING, 4GB

    CPU COOLER CM| RR-B10-212P-G1 RT

    MEM 4Gx2|KST KHX1600C9D3K2/8GX RT

    CASE ROSEWILL|CHALLENGER RT

    PSU ANTEC|650W EA650 RT

    CPU INTEL|CORE I5 2500K 3.3G 6M R

    ASUS XONAR DG 5.1 CHANNELS PCI INTERFACE SOUND CARD
     
  10. RasmusP

    RasmusP
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    I bet that it's your i5. It's it overclocked?
    I have a I7 2600k @ 4.4 GHz and I struggle to keep 60 fps with more than 15 cars on the grid if I activate a few apps or use mod content.
    The problem is that mods are often not as well optimized compared to the Kunos content.
    You have more "useless" "tris" and stuff.
    Which is cpu load increasing!

    Sadly ac uses only 2 cpu threads so although you have 4 cores, your cpu is hanging in the single thread performance limit and can't be utilized to its full extend.
    With a modern amd cpu this gets worse. They have a low single thread performance but a lot of cores! They get stuck in their single thread limit with only showing 25% overall cpu load!

    There are a few things you can do:
    - put reflections to static
    - deactivate all apps that are not essential for you
    - run lower shadow settings
    - reduce rendering distances via cm for reflections
    - activate the cpu optimizations of the shader patch (but not the cpu load increasing gpu optimization!)
    - overclock your cpu
    - overclock your ram
    - kill all tasks that aren't needed for running ac

    Sadly, that's about it. It's why with new builds I always recommend a 9600k or 9700k. You can always splash a new gpu into the pc but replacing the cpu, mobo, ram is a pain.

    Hope that helps a little and clarifies things :)
     
    • Like Like x 1
  11. Rogerbee

    Rogerbee

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    Ah feck, I didn't see that there were 2 maximum pre-rendered frames settings in NVidia Control Panel. One ordinary and one VR. I've set them both the same now and will see what I get then.
     
  12. bsmooth

    bsmooth

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    No not overclocked. It looks like I'm pretty lucky I'm doing as well as I am then !
    When I check CPU usage its around 92%, but its steady. That must be why I'm getting CPU at 99% sometime, and getting a warning. Also pretty good I put the CPU cooler in there as well.
    I appreciate the help, getting better at building PC's, but sometime don't understand what is actually going on, but I do know cooler is always better..
    Guess it wouldn't be worth upgrading the CPU then on such an old motherboard ?.
    I just upgraded the GPU from a EngTX560 Ti DCII Top, and that just barely did 10 cars at a time.
    I appreciate the help.
     
  13. RasmusP

    RasmusP
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    Upgrading on the same motherboard would be useless indeed. While my cpu with hyperthreading and therefore 8 cpu threads won't get above 60% load in ac, I doubt I have more than 5 fps more than you.
    Overclocking would be a huge gain in performance though! Great guides out there, easily done on your p67 chipset!
    Only problem might be your kinda small cooler.
    I have a very very bad airflow case but a thermalright le grand Macho rt. Look that beat up, lol.

    What you should do: monitor and log your cpu temperature. Easy program would be openhardwaremonitor :)
    Tell me your temperatures while gaming and I'll tell you how far you can overclock :)
     
  14. Leonardo Ratafiá

    Leonardo Ratafiá
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    You just need to experiment yourself, you can have 2 identical pc hardware configuration, same could and gpu and even get different results using same settings.
    Vsync on introduces input lag
    Vsync off and you get stuttering
    Best thing is having a freesync o gsync monitor but are expensive
     
  15. Rogerbee

    Rogerbee

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    While freesync is essentially an AMD feature, I just read that newer NVidia drivers mean that you can set GSync up on a monitor that has Freesync, you just need the right driver.

    If you have the right driver NVidia Control Panel will look like this:

    [​IMG]

    It will only work via a DisplayPort connection. Which is a pity for me as I recently borked mine!
     
  16. neilparky

    neilparky

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    I'm currently using a 75hz variable refresh monitor overclocked to 77hz and capped at 73fps with Vsync off, no tearing and no frame time spikes even on an FX8350 @4.6 and 3gig 1060.

    This guy explains it well.

     
  17. Rogerbee

    Rogerbee

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    Oh well, it's academic for me as my display port is knackered. Would it work for 60hz via HDMI?
     
  18. Rogerbee

    Rogerbee

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    Looks complicated to me, what I have works and I think I'll stick with it.
     
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