Using RTSS to cap FPS causes 1 core to constantly be close to 100% usage ?

Discussion in 'Rivatuner Statistics Server (RTSS) Forum' started by DisGuy, Nov 15, 2020.

  1. DisGuy

    DisGuy New Member

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    Hi,
    i hope I'm not just being a noob and making a fool of myself by missing something super obvious, but I noticed that if i use the normal RTSS FPS cap or the Scanline sync with Apex Legends, the game kind of hogs one thread close to 80-100% constantly. Even in the login screen, where nothing intense is happening.

    So i have my Apex capped in Origin with the "fps_max 300" command.
    I open the game and stay in the "login" screen, where you need to press "Continue". - 300fps @ 20%ish GPU use.
    My overall CPU usage is around 10-17%. The highest used core is 40-60% used.
    If i cap with RTSS to 99fps or whichever number <300, my highest used core is then 80-100% used.

    My expectation is if I'm getting 300fps at 50-60% core use, to get less than 60% use at 100 fps, no? Is RTSS injecting pauses which make it only seem like the 1 core is at high utilization or something?
    Because I'm not really sure if the game is performing worse or not because of the maxed core, since the game is DX11 and high single core use is very common anyway.

    What am i missing here?
    Is this normal / expected behavior?

    Thanks. Any help is appreciated.

    PS.
    Before you say "if you can't even tell if there's an actual performance hit, then what's the difference?"
    Well the potential cost of +50% thread usage is a bit high, even if the result is smooth gameplay with reduced motion blur (referring to the monitor setting).
    I've been testing many Nvidia, monitor, game settings for Apex, all of which have some effect and the game's thread just suddenly becoming maxed is an effect too suspicious to ignore.

    *System info*
    Win 10 20H2
    Ryzen 2600
    GTX 1070 (457.09)

    Nvidia CP: Apex settings : LowLatency OFF / Vsync OFF

    Afterburner 4.6.3.15840 Beta 2
    RTSS 7.3.0 Beta 6

    also tested on a non beta Afterburner,RTSS 7.2.0
     
    Last edited: Nov 15, 2020
  2. Andy_K

    Andy_K Master Guru

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    A rough description is RTSS is "busy" actively waiting for the time to pass to let the game render another frame just in time.
    Nothing to worry about, it's by design.

    In the new RTSS 7.3 (beta) there is now a passive waiting which doesn't hog the CPU,but lacks a bit of timer precision:
     

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