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AMD Details Driver Fix For Radeon RX 480's Controversial, Spec-Exceeding Power Draw (pcworld.com)

Posted by msmash on from the fixing-things dept.

AMD's 150-watt Radeon RX 480 apparently draws more power than it is supposed to. According to Tom's Hardware blog, AMD's new graphics card used an average of 168W under load. Furthermore, the publication found that card pulled up to a whopping 90W over the motherboard's PCI-E slot, far exceeding the 75W maximum the slot it rated for. PC Perspective's findings were similar, with Witcher 3 title consuming over 190W of sustained power draw when the RX 480 was overclocked. Worse, the blog discovered that AMD's card drew 7 amps over the PCI-E slot's +12v rail, which is rated for 5.5 amps maximum. These issues could theoretically (but not likely) damage lower-end motherboards in extreme circumstances, writes PCWorld. The chip company last week addressed the concerns, noting that it will soon release a software fix. In a new statement to PCWorld, the company adds:"We promised an update today (July 5, 2016) following concerns around the Radeon RX 480 drawing excess current from the PCIe bus. Although we are confident that the levels of reported power draws by the Radeon RX 480 do not pose a risk of damage to motherboards or other PC components based on expected usage, we are serious about addressing this topic and allaying outstanding concerns. Towards that end, we assembled a worldwide team this past weekend to investigate and develop a driver update to improve the power draw. We're pleased to report that this driver -- Radeon Software 16.7.1 -- is now undergoing final testing and will be released to the public in the next 48 hours. In this driver we've implemented a change to address power distribution on the Radeon RX 480 -- this change will lower current drawn from the PCIe bus. Separately, we've also included an option to reduce total power with minimal performance impact. Users will find this as the "compatibility" UI toggle in the Global Settings menu of Radeon Settings. This toggle is "off" by default. Finally, we've implemented a collection of performance improvements for the Polaris architecture that yield performance uplifts in popular game titles of up to 3%. These optimizations are designed to improve the performance of the Radeon RX 480, and should substantially offset the performance impact for users who choose to activate the "compatibility" toggle.

7 of 157 comments (clear)

  1. Take the PCIe logo off the box by CajunArson · · Score: 5, Insightful

    These cards may or may not damage your motherboard, but there is zero doubt that in the default configuration -- not some out of spec hacked BIOS configuration -- they are not compliant with the PCIe standards.

    Putting that PCIe logo on the box is therefore deceptive marketing and AMD should be held accountable here.

    --
    AntiFA: An abbreviation for Anti First Amendment.
    1. Re:Take the PCIe logo off the box by CajunArson · · Score: 5, Insightful

      The new drivers in the default configuration are still out of spec with PCIe.

      The fix that AMD applied is to route more power from the 6-pin PCIe power cable to reduce the power drawn from the motherboard. The motherboard is now supposed to be in-spec (of course, independent testing is necessary) but by defintion the 6-pin PCIe cable, which was already providing more than the specification-rated 75W, is definitely out of spec.

      Now as a practical matter, the extra power draw through the 6-pin cable will not cause problems with any halfway decent PSU. However, just saying "oh it won't damage your computer in a practical scenario" is not the same thing as complying with the PCIe specification. Actual compliance with PCIe is required to show the logo on the box and advertise compatibility.

      The fact that there is now going to be a non-standard "optional" mode that complies with PCIe is nice, but unless it's the default mode out of the box, it's not enough.

      --
      AntiFA: An abbreviation for Anti First Amendment.
    2. Re:Take the PCIe logo off the box by Luthair · · Score: 2, Insightful

      I watched PCPerspectives video the other day and they mention this is actually the norm and all cards do it to varying degrees. They also spoke with motherboard vendors who didn't want to go officially on record who said that they didn't anticipate any issues with momentary draws higher than spec.

    3. Re:Take the PCIe logo off the box by CajunArson · · Score: 3, Insightful

      Transient spikes above the average are not the issue here and there's actually a whole different section of the PCIe power specification that deals with the maximum transient spike levels and the maximum allowed rate-of-change in current draw. As long as the transients don't exceed the ratings in the specification they are OK and are to be expected.

      The issue here is that on average the Rx 480 was easily drawing well above the limits for a motherboard slot. Over the long-term, this sustained out of spec power draw can cause problems on motherboards, particularly cheap motherboards. When you consider that a low price was a major advertising point on the Rx 480 launch, expecting all of the Rx 480 owners to be running premium X99 motherboards that cost $300+ -- which is exactly what AMD did when demonstrating the Rx 480 on-stage at Computex -- is unrealistic.

      --
      AntiFA: An abbreviation for Anti First Amendment.
    4. Re:Take the PCIe logo off the box by K.+S.+Kyosuke · · Score: 1, Insightful

      Putting that PCIe logo on the box is therefore deceptive marketing and AMD should be held accountable here.

      So should nVidia, perhaps?

      --
      Ezekiel 23:20
  2. It is hard to imagine that AMD missed this... by FlyHelicopters · · Score: 4, Insightful

    AMD has smart people working for them, how they missed this and launched the card I'm at a loss to explain...

    Unless they didn't miss it and hoped no one would notice... Or the left hand didn't talk to the right hand...

    As for the extra power coming from the 6-pin PCI-E connector, that doesn't bother me so much, most modern power supplies can do that just fine.

    I said *most*, some won't be able to, this is indeed a problem, but for most people the fix is just to update the drivers and the few that it isn't, to put it in "compatibility mode"

    The problem is, the people who need *compatibility mode* are exactly the people who won't know that and won't do it.

    I think it is a mistake to not make compatibility mode the default and let people manually adjust to the higher draw mode.

    1. Re:It is hard to imagine that AMD missed this... by Anonymous Coward · · Score: 2, Insightful

      the spec may be overly conservative, but that's neither here nor there. but it can't be "wrong" by definition. the spec is the spec. it might be based on old data, and a relaxation might be in order, but really... the connector technology hasn't changed. whatever the reason for the conservatism, nothing material has changed.

      is a spec relaxation warranted? maybe. but that's not the same thing as "the spec is wrong".