VR: 90 FPS constant as soon as mouse is moved

Discussion in 'Technical & Support' started by Vranq, Oct 18, 2021.

  1. Vranq

    Vranq Registered

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    I just made a strange discovery: In rF2, I average around 70 FPS (WMR @ 200% SS) on the track when I turn off motion smoothing. The GPU frame times "bounce" up and down at regular intervals in a range between about 5 and 12ms.

    As soon as I start moving the mouse, which is not even visible on the track, I get a constant frame rate of 90 FPS and the GPU frame times stay just as constant at a low level of about 5ms. This only lasts as long as the mouse is being moved. As soon as it stands still, the FPS goes down again and the frame times bounce up and down again regularly.

    Does anyone have an explanation for this phenomenon and how I might be able to get the 90 FPS consistently without a hand on the mouse?

    (My PC: AMD Ryzen 7 5800X, ARCTIC Liquid Freezer II 280 , MSI X570-A PRO AMD X570,16GB G.Skill RipJaws V DDR4-3600 DIMM CL16, Powercolor RX 6900XT, Bitfenix Whisper Series 850 W, Windows 10 Pro)
     
  2. lagg

    lagg Registered

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    Just a theory.
    Could be that your rF2 loses the focus and then there are fps drops. But if you move the mouse, avoids that other programs take the focus.
    Open your Player.json with a text editor and configure these parameters in this way.
    "Active Sleep Time":-1,
    "Inactive Sleep Time":-1,
    "Pause If Focus Lost":false,
     
  3. Vranq

    Vranq Registered

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    Good idea but unfortunately didn't work. I made a small video (sorry for lousy quality). This is before going on the racetrack. On the racetrack there are only GPU frametime spikes and CPU frametime stays at a low level (4-5ms).

    Edit:
    As if it isn't crazy enough already, I've just discovered that X-Box controller movements and keyboard keystrokes also produce the same effect. It even goes so far that I can create a workaround for constant 90FPS using joystick programming on my Warthog. I simply loaded the programming for IL-2 Great Battles and flipped a switch that constantly "spams" the same letter (programmed for retracting the flaps) and the result: constant 90 FPS.
     
    Last edited: Oct 18, 2021
  4. lagg

    lagg Registered

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    Very strange.
    I've no idea about this. I can't help you, sorry.
     
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  5. Magus

    Magus Registered

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    Interesting, I'm going to test this shortly as I suffer the same issues.
     
  6. Vranq

    Vranq Registered

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    It goes even further. A similar effect can be seen when playing on monitors. The difference is that the FPS are fixed to 75 if mouse is still and 140 FPS if mouse is moved regardless of the chosen screen resolution (tested with FullHd and 3840x2160).
     
  7. Vranq

    Vranq Registered

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    The problem could be solved by activating AMDs Anti Lag. 300 FPS with monitor (even @3840x2160 and 4x MSAA) and 90 PFS in VR.
     
    Kelju_K, atomed and lagg like this.
  8. Kelju_K

    Kelju_K Registered

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    Very interesting find. I know mouse movement has the highest priority of all in windows. It is even visible in oscilloscope when monitoring cpu voltage. it creates huge transient spikes when ever mouse if moved.
    I bet it's to ensure good user experience even with the slowest of the slow pc's.
    I mean if mouse was lagging, nobody would be able to use the pc.

    But why would it (moving the mouse) cure low fps ingame??? very strange...

    Did you mean that the AMD's anti lag does the same as moving the mouse?
     
  9. Vranq

    Vranq Registered

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    The effect of anti lag is much better than moving the mouse. The increasement in fps is huge. So it actually does'nt matter a lot in VR because the fps are limited to 90 there. But this behavior is only with rF2. I guess it has something to do with my system configuration and the fact that my Windows 10 installment is pretty old.
     

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