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Frame Limiting - CPU Busy wait loops, Anti-Lag and OBS Studio Questions

Discussion in 'Rivatuner Statistics Server (RTSS) Forum' started by Can Çeralp, Aug 29, 2019.

  1. Can Çeralp

    Can Çeralp Member

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    GPU:
    Rx 480 8Gb
    Hey,

    (I'm sorry if the questions I'm about to ask are asked before but I have searched for more than a week and couldn't find any. That's why I start a new topic here)

    I am trying to record my games with OBS studio. Learned lots of things from OBS forums and been using RTSS already for years. My questions are;

    1) I have i5 6500, which is a mid-low CPU for today's standards, mostly low. So I'm trying to leave some room for OBS by doing two things
    a) limit the game FPS with RTSS (works wonders as well as smoothness)
    b) Set higher priority to OBS in Task Manager (mostly working, depending the game's hunger)

    They seem to work most of the time, especially when the game doesn't choke the CPU. My question is; RTSS limiter works by sending busy wait loop to the CPU and holds it until the en of the set limit. This busy wait loop is shown as a CPU load on measurement applications (like AMD Radeon metrics, MSi Afterburner etc.). Does it really act like a load and steal CPU from OBS? In other words, does these busy wait loops effect OSB and make it wait/lag/stall/slow down, too?

    2) I have an RX 480. I want to use the newly introduced Radeon Anti-Lag feature since I only have a 60 Hz display and it works best at lower FPS values. However I wonder if RTSS would effect it's working? Because AMD doesn't let users to use Anti-Lag and FRTC (Radeon's own FPS limiter) at the same time. Apperantly Anti-Lag (or AMD) doesn't like limited FPS?

    On a second thought, this may be because of Anti-Lag needs to be quick for every calculation, FRTC is effectively slowing down the GPU for FPS control. Their mentalities can conflict with each other, I get it. However "RTSS and Anti-Lag together" is another question. Because they both interfere with the CPU. Would RTSS's strict CPU timings render Anti-Lag ineffective?

    Bonus question: What would be the benefit of using a frametime limiter over framerate limiter?

    Thanks.
     
  2. HiAlgoBoost

    HiAlgoBoost Member

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    An additional frame pacer will mess up Anti-Lag, sorry about that... On the other hand, if you are CPU-limited (meaning that without the limiter the game can run faster), and the frame pacing is done on the game thread - then you don’t need Anti-Lag (you get that effect automatically). You can use Chill with minFps==maxFps to do this limiting (I don’t know exactly what RTSS does - but it might introduce extra lag... or not...).
     
  3. Can Çeralp

    Can Çeralp Member

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    GPU:
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    Thanks.
    I'm trying to dissect and understand what you say.

    First thing, Anti-Lag and Chill doesn't work together. Enable one, the other is disabled automatically. BTW, Chill and FRTC are mostly same thing for the newer drivers. Because when I set a minFPS==maxFPS (say 30) in Chill by using Radeon Overlay, a small notification says "FRTC is set to 30FPS".

    Second, let me go over an example. For Shadow of The Tomb Raider or a The Division, if I limit FPS to 30, not CPU nor GPU reaches to %100. So, I'm not limited in any way. GPU = 40-50%, CPU= 70-80% This is the scenerio I want to use RTSS + Radeon Anti-Lag

    Third, when you say "additional frame pacer" did you mean using two or more FPS limiter at the same time?
     

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