Vega 56, terrible DPC latency when idle; works well on load.

Discussion in 'Videocards - AMD Radeon' started by furkandeger, Jan 24, 2019.

  1. furkandeger

    furkandeger New Member

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    GPU:
    SAPPHIRE R9 290X BF4
    Hi guys, just got myself a Vega 56 (ASUS ROG Strix) however I'm having terrible choppines, mouse lag, sound crackling when the card is idle... In games it's perfectly working.

    Checking the GPU-Z, I discovered that whenever the memory clock goes lower than 700 Mhz, this happens (with terrible DPC latency). So I configured the global wattman to keep memory at 700 mhz minimum (p2, I guess) and it works fine now but it still makes me wonder if it's a hardware defect or not...

    I'm on Windows 10 Pro x64 (1803), yes I tried DDU and a previous driver. I have two monitors and I got them running via HDMI + DP (respectively 60 hz + 144 Freesync) but I also tried single monitor and it was the same... Any ideas?

    Here are some screenshots from LatencyMon when the card is idle:

    https://i.postimg.cc/zGjPY8GL/1.png
    https://i.postimg.cc/sx7w6RLg/2.png
    https://i.postimg.cc/k4kTv5fH/3.png
    https://i.postimg.cc/FKCW1pcN/4.png

    System specs are:

    ASUS Crosshair VI Hero
    Ryzen 7 1700
    Corsair Vengeance LPX DDR4 16 GB @ 3000
    NZXT Kraken X62
    ASUS ROG Strix RX Vega 56
    Corsair HX850i
    Two ssds, two hdds.

    I guess that's it.
     
  2. mbk1969

    mbk1969 Ancient Guru

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    GPU:
    GeForce GTX 1070
    https://postimg.cc/qhxckpfc

    The longest DPC routine is 24 ms which is not that bad time span, but the fact that there are several more drivers (and devices) with practically the same DPC times makes it worse.
    Have you tried videocard at idle after disabling the network controller?

    PS You can try this tweak
    https://forums.guru3d.com/threads/windows-line-based-vs-message-signaled-based-interrupts.378044/
    and although it can`t help with DPC it can help a bit with ISR latencies.

    PPS We saw several cases here when gurus got rid of strange behaviours after cleaning the CMOS, after updating or downgrading the BIOS (either motherboard or videocard).

    PPPS Have you installed a proper chipset drivers?
     
    Last edited: Jan 24, 2019
    furkandeger likes this.
  3. furkandeger

    furkandeger New Member

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    GPU:
    SAPPHIRE R9 290X BF4
    Thank you for your comment.

    I tried your utility and there was only High Definition Audio Bus that was not working in MSI mode so I checked it for MSI but it didn't work after reboot (I mean, it still has a positive number)

    I changed several BIOSes for mobo, for the gpu there aren't any other alternative bios versions but re-flashed the same bios only to have no effect.

    Chipset drivers are properly installed. I tried with the network card disabled but it also didn't help. Only thing that seems to help is disabling the Vega 56 from device manager.
     

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