0 Replies Latest reply on Jul 28, 2017 5:30 PM by kasper93

    Video playback issues, audio glitches, high dpc latency on dxgkrnl.sys

    kasper93

      Hello,

       

      I've been diagnosing this issue for three days already and I think I have pretty good idea what is going form user point of view. I will try to keep this post short and I hope someone will care enough to reply.

       

      The problem:

      Certain video files are unplayable due to very frequent audio glitches caused by significant DPC latency caused by dxgkrnl.sys.

       

      Observations:

      • Problem occurs with certain video files (my test file is Sony_4K_HDR_Camp.mp4, but it happens with any more demanding file). Those little bit more dependent on hardware resources, but still lightweight enough that they should play without any problem on my hardware.
      • Issue occurs with any media player. With and without DXVA decoding. It is not decoding issue. There is plenty CPU power to handle videos I test.
      • Audio issue is system wide during video playback.
      • Issue seem to be caused by events relented to core clock control. While video playback clock fluctuate from 600-800MHz to accommodate variable load from media player.
      • To workaround the issue one need to force full (higher) clock on GPU. Easily done by starting PCI-E render test in GPU-Z, which forces full clock on GPU core. This reduces dxgkrnl.sys latency 50 times, therefor fixing the playback issue.

       

      It looks like currently GPU load which require higher clock, but is not heavy and constant enough to keep the clock at specific level causes very big issues with DPC latency. Video is unplayable on my current graphic card. I've connected old HD5870 and it is fine, because it does have only three power states and core clock is stable during playback. But there were also few cracks, but nothing abnormal like with described issue.

       

      I suspect that it might be either too aggressive power management and too slow clock speed adjustments resulting in problems with not heavy load. Like video playback that require little bit more processing power. Or it might be some other issue that is hidden behind the symptoms I described. I've read it isn't uncommon problem to have issues with latency on Windows 10.

       

      Hardware:

      ASUS X99-A/USB3.1

      Intel I7-6800K

      G.Skill F4-2666C15Q-32G

      ASUS R9 390 Direct CU II

      Windows 10  (15063.483)

       

      I can provide xperf trace if necessary, but the cause is very obvious so you will not see anything else there anyway. That's why I'm not providing exact number, because they are in fact irrelevant, relevant is the damage it cause.

       

      I wanted to upgrade graphic card soon, but frankly I now scared to pick AMD again to face similar issues ;/ I hope someone with reply so we can at least try to resolve issue either on my end or on yours. And if it is Windows bug it is even more critical to take care for you, because it make your products look bad.

       

      Regards,

      Kacper