[Question] RX480 8G draws 80W+ from the PCIe slot - what does this mean for me?

Discussion in 'Videocards - AMD Radeon' started by artisticMink, Jun 29, 2016.

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  1. PrMinisterGR

    PrMinisterGR Ancient Guru

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    AMD in their live stream said "Power: 150W". That was obviously for the whole card, and if the measurements are correct, then it was false. The whole reference design is in their hands, so they can't throw the allegation to AIBs now. I believe that they will make it go out of spec on the 6pin connector (which shouldn't really have any problem unless your PSU is a tin can with tin cables), instead of playing the Planet of the Rapes on the motherboard.
     
  2. vase

    vase Ancient Guru

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    i've already seen many people do it... but i can just underline: dont mix up the 75+ watt pci-e SLOT problem with a ~10Watt (160W) overshoot of the AMD communicated TDP value (150W).

    1.) with stock clock, that is 1120Mhz, we are definitely inside the 150W range

    2.) and more importantly: thermal design point does NOT designate maximum possible PEAK power draw!!!
     
  3. PrMinisterGR

    PrMinisterGR Ancient Guru

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    It wasn't a TDP value, it was a POWER value, I saw it live.

    [​IMG]

    Here is the video link with the timestamp.

    If the boost clock makes the PCIe slots go out of spec on power, of all things, then it shouldn't boost, or be advertised with the boost clock.

    Thermal design power wasn't mentioned even once in the presentation. The only term used was the term "power", designated at 150W. Taking into account the 75W limit on the PCIe slot, the 75W limit on the 6-pin PCIe connector, and a card who is designed like this one, it was obviously referring to total power draw, not TDP.

    Therefore, if the cards do behave like the tests indicate, AMD f*cked up. Their only choices now are either to cull the boost clock more aggressively via drivers, a bios update that will make the card use only the 6-pin out of spec (still lame, but not really dangerous), or to recall the cards.
     
    Last edited: Jun 30, 2016
  4. Archimonde

    Archimonde Banned

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    OCUK lists RX480 only with 110W TDP value, nothing else. No 150W, certainly not 170W :p

    Now 7 independent tests have confirmed the result
     

  5. vase

    vase Ancient Guru

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    1) there is no "total power draw".

    2) no, amd never said the 150W is a max power draw. "power" can mean anything. from "typical power during gaming" to "typical power when under load" to "typical power when mining bitcoin"...
    it just says power, not "max", not "total", not "absolute upper limit"

    3) power draw will always increase if you overclock, so there can't be an upper limit. you can always draw more power by increasing voltage and core clock. until the chip at some point says something similar to the words "no no no it's enough for me now"

    again i answer while the 75W PCIe slot spec issue is mixed up with things like "max power draw"


    well then its ocuk's fault?! they got a spec from AMD along with the delivery and mistake ASIC power with TDP?!
    i mean amd always stated 150 W (power / tdp)


    also and this should finalize the topic... to clean up a little further...

    7850 had one 6 pin only was specified 150 TDP and sucked 170W under load or when oc'd respectively... no one gave a fart about it.

    [​IMG]
     
    Last edited: Jun 30, 2016
  6. vase

    vase Ancient Guru

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    also found that GTX 555 had as well a indicated tdp of 150 with only one 6-pin connector.
    using more than 150W when overclocked.

    also no board damages reported. nothing.
     
  7. PrMinisterGR

    PrMinisterGR Ancient Guru

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    You are saying that presenting it with the title "Power: 150W" and designing it with a single 6-pin that gives it a total in-spec power consumption of 150W, is irrelevant? Is that what you're saying? Like, seriously? We pretend now that the one has no relation to the other?

    I agree completely with that. You can't ask for 83W from the PCIe slot on a reference, non-overclocked card. Furthermore, allowing the change of the power limit of said card through software, is downright irresponsible. The card is over spec by default, and they allow you to **** it up on top, without even overclocking. Just by the power limit slider which should have been locked with an electrical design like that. There are reports that while playing the Witcher it reaches 200W, half of it drawn from the motherboard. WTF.

    No it didn't. That's total system power draw, not GPU draw. Even if it was GPU draw, the 480 does that through the PCIe slot, instead of the PSU cable which would be ****ty, but ok with any relatively modern PSU.
     
  8. vase

    vase Ancient Guru

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    Well to my understanding that value itself is not a problem for the mainboard.
    As a 2x CFX would draw 150W from PCIe bus, a 3x CFX draws 225W?! 4x 300W?

    I don't know the max limit, but one card going a little over spec can't be the big problem it is being depicted as.

    But yes, it is to be fixed for sure, just for convenience sake.
    And secondly because if someone decides to do quad CFX he indeed may have a problem... Or the Mobo just shuts down (thats what i think)
     
  9. PrMinisterGR

    PrMinisterGR Ancient Guru

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    There is a reason that PCIe is max 75W man. That 24+8pin has limits on what it has to power. Don't forget also that this is a budget card. I'm sure my 12-layer, diamond choke, premium copper, solid Japanese capacitor Sapphire motherboard that used to cost 300 euros, won't give a ****. My neighbor's ****ty B170 ECS with his i5-3330, and the already filled two memory slots, how will that take the 100W on the 75W spec'd PCIe?
    How will his cheap Corsair 550W PSU take the switch from the 7870 where it gave all the power through the double 6pins, and now has to get all that through the 24 pin of the ****ty mobo?

    This is poor man's VR. It can't demand high-range out of spec components to work.
     
  10. Ryu5uzaku

    Ryu5uzaku Ancient Guru

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    Now now, considering some decent z170 board has 3 pci-e lanes to power maybe 4. Those 24+8 will be feeding upwards 300 watts. Even cheap z170 won't budge from this "issue" I can see some 50€ crap board possibly reacting to it.

    What I do not understand that why for some it eats up 200watts in witcher 3 and for some not even close.

    http://www.techspot.com/review/1198-amd-radeon-rx-480/page7.html
     
    Last edited: Jun 30, 2016

  11. PrMinisterGR

    PrMinisterGR Ancient Guru

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    If AMD is lucky, then it's indeed a batch issue that's fixable.
     
  12. AlmondMan

    AlmondMan Master Guru

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  13. Barry J

    Barry J Ancient Guru

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  14. Ryu5uzaku

    Ryu5uzaku Ancient Guru

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  15. Fox2232

    Fox2232 Ancient Guru

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    Just for curiosity, dues that fiend of yours have MB with Additional PCIe Power supplement connector?
    I think they are quite common and are ones who decide if you can or can't pull that kind of power.
     
    Last edited: Jun 30, 2016

  16. Twiddles

    Twiddles Maha Guru

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    What about the BIOS? My GTX 750 Ti uses the PCIe slot for power, I modded it to ~63w for better overclocking. How about the AMD R9 480?
     
  17. Archimonde

    Archimonde Banned

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    I was wondering the same thing. If each slot is allowed 75W absolute maximum (maximum is 66w with 75w providing extra room) then have four slots means 300w, but I don't believe any mobo will handle that, most of the power is usually provided by pcie external connectors.

    Even if the board total can handle 300W, 100w on a single set of traces that are rated for 76 could cause problems, it could not.

    There's no excuse for this. If it draws 20w more than claimed, it should be drawing that extra from the 6pin and not from motherboard

    It should have an 8 pin.
     
  18. chuck216

    chuck216 Active Member

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    I think people are being too harsh on the RX 480's power consumption numbers. Yes it does draw the limit of what it's 6 pin connector can provide.

    But consider this: It performs neck and neck with the R9 390 which requires a 6 pin and an 8 pin connector.
     
  19. s0x

    s0x Member Guru

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    @chuck216, most of the issue is with drawing that extra power from the PCIe slot on the motherboard, not from the PCIe cable from the PSU.
     
  20. zer0_c0ol

    zer0_c0ol Ancient Guru

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    It means absolutely nothing

    [​IMG]
     

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