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    Some AIBs gimping power delivery causing 3080/3090 instability

    Discussion in 'Gaming (Software and Graphics Cards)' started by hfm, Sep 25, 2020.

  1. hfm

    hfm Notebook Prophet

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    Apparently some AIB vendors were designing under-spec power delivery causing instability at "GPU Boost" clocks if the card had the headroom. The issue is being investigated by Igor's Lab.

    Apparently it has to do with the filter caps on the power delivery that is closest to the GPU. The reference spec uses 5 cheaper POSCAPS and 1 more expensive MLCC array. Some vendors are using 6 POSCAPS, which causes noisy power delivery and instability at higher clocks. Granted this is happening during "GPU Boost", in which the clocks run way over the top spec, 1710Mhz in the 3080 case. GPU Boost will, if power delivery and temps have head room, boost all the way up to 2000Mhz or more. This is where the instability rears it's head.

    Seems some vendors are using 6 POSCAPS, some doing it correctly and using at least 1 more expensive MLCC array. nVidia FE edition uses 4 POSCAP and 2 MLCC. Looks like Asus was the vendor that did the best job with ALL SIX having an MLCC array.

    It seems the easy fix is just new firmware that limits GPU Boost so the instability doesn't rear it's head, anything over 1710MHz was all gravy and not OFFICIALLY spec anyway. But yeah, great job by some AIBs in doing cheap builds.

    I guess good thing we have to wait a little longer to actually get a card, nVidia should probably yell at these vendors. :)

    Makes me wonder if this issue has anything to do with the supply chain problem for the 3080, and nVidia is just making them stay mum about it while they get new firmware out there. Like Jay says in the video, I really doubt any but the AIBs that care the most about their reputation will retool assembly lines and designs to switch to the more expensive filters. Actually, I guess if the AIB cared that much they are probably one of the ones using at least 1 MLCC array to begin with.

    https://www.igorslab.de/en/what-rea...tabilities-of-the-force-rtx-3080-andrtx-3090/

     
    Last edited: Sep 25, 2020
    hfm, Sep 25, 2020
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  2. hfm

    hfm Notebook Prophet

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    hfm, Sep 26, 2020
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  3. Khenglish

    Khenglish Notebook Deity

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    Historically gpus would only have ceramic caps directly behind the core. With Maxwell there was clocking improvement putting big electrolytic caps behind the core too for more capacitance. Some manufacturers seem to have taken that too far with this latest gen.

    I do not like the all ceramic cap designs, unless they used super expensive 50uf or 100uf ceramic caps. Seeing higher than 22uf is very rare due to cost.
     
    Khenglish, Sep 26, 2020
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  4. Prototime

    Prototime Notebook Evangelist

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    "POS CAP" appears to be a very appropriate name for them, given the circumstances. I'm glad some companies are addressing the issue. But the many who haven't? Their silence is deafening.
     
    Last edited: Sep 26, 2020
    Prototime, Sep 26, 2020
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  5. hfm

    hfm Notebook Prophet

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    I feel kind of good that after seeing all the reviews the two I was most highly considering were
    1. Asus TUF
    2. EVGA XC3
    3. nVidia FE
    Just because based on reviews they seemed quieter than the FE model and they can also fit in my eGPU.. 55mm max height requirement and those two AIB are the only ones that are not super tall. Seems like it was a good vendor choice for other reasons as well. lol..
     
    hfm, Sep 26, 2020
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  6. hfm

    hfm Notebook Prophet

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    LOL This gets better all the time... looks like not only caps, or perhaps at all

     
    Last edited: Oct 1, 2020
    hfm, Oct 1, 2020
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  7. Tyranus07

    Tyranus07 Notebook Evangelist

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    Well the good thing is the problem seems to be solved with a simple driver update, pretty nice-
     
    Tyranus07, Oct 2, 2020
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