Glitches on hardware render - bad GPU?

Discussion in 'iMac' started by Kingsly, Jul 22, 2019.

  1. Kingsly macrumors 68040

    Kingsly

    #1
    Noticed recently that when I go to render out of Resolve I get bad, sort of cascading visual glitches in the final output for h.264 and HEVC. ProRes, mercifully, seems fine.

    Played around with it and get the same glitches in Adobe Media Encoder. However, if I uncheck "Hardware Rendering", the output renders just fine, albeit slowly.

    Anyone ever seen this before? I'm concerned that it may be the precursor of a failing GPU.
     
  2. Ledgem macrumors 68000

    Ledgem

    Joined:
    Jan 18, 2008
    Location:
    Hawaii, USA
    #2
    I have the same problem, although with different applications. The good news is that it's not a faulty GPU. Evidently there's a different encoder that it used when the GPUs handle the encode, compared with when your main processor does it. The GPU-based encoder stinks, is the best I can say; output quality even on the highest settings is worse than output from the CPU encoder on lower settings, particularly with visual artifacts that are similar to what you're describing.

    The websites I found discussing this problem were talking about it in reference to Nvidia graphics cards, so it's not a question of AMD versus Nvidia chips, either. It'll probably improve in the future, but for now I do the same as you: disable hardware acceleration/rendering, and force it over to the CPU.
     
  3. Kingsly thread starter macrumors 68040

    Kingsly

    #3
    That's encouraging to hear. Yeah in my case it's always a bunch of white/grey/black rectangular glitches cascading diagonally across the upper right third of the frame.

    I wonder at what stage the driver got mucked up... this computer was a solidly cranking out non-glitched video until six-nine months ago. Also, now that I'm thinking of it, within a similar timeframe the SMC got bugged. Wake from sleep takes sometimes five or more minutes of me frantically pounding on the keyboard and hitting the power button. Resetting it sometimes makes it better for a few days. Sometimes not.

    Don't feel like I'm particularly hard on my graphics cards (video editing, rarely visual effects, and light gaming when the bug hits) but in context I've had them be the first component to fail across almost every Apple computer I've had since the switch to Intel processors...
     
  4. Ledgem macrumors 68000

    Ledgem

    Joined:
    Jan 18, 2008
    Location:
    Hawaii, USA
    #4
    It sounds like you might still have some hardware-based things going on. It is odd that you were encoding without these artifacts and it only happened recently... and now I'm also not sure if what you're describing is the same thing I get. For me, the video isn't "glitched," but shows odd artifacts that aren't present with the CPU-based encoder (for example, a straw hat's grid pattern appears to be "shifting" every second or so with the GPU encoder, whereas it's stable with the CPU encoder). I still don't think hardware failure would explain that; it's more likely that the encoder was updated with some software update and started causing your problems, but I can't be certain.

    Same here, sadly. It makes the prospect of eGPUs a little more exciting; perhaps removing them from the main system will help them to last longer. Even if they still fail more quickly than the rest of the system, at least we'll be able to swap them out without having to replace the entire computer.
     

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3 July 22, 2019