Following up on this week's Radeon RX 480 launch, there has been some questions raised about the power consumption of the card. This is after some sites whom directly tap the power rails feeding the card discovered that at least some of their samples were pulling more than the standard-allowed 75W over the PCIe slot and/or 6-pin PCIe external power connector.

To that end, it would appear that AMD's staff is working weekend duty, and they have just sent over the following statement.

As you know, we continuously tune our GPUs in order to maximize their performance within their given power envelopes and the speed of the memory interface, which in this case is an unprecedented 8Gbps for GDDR5. Recently, we identified select scenarios where the tuning of some RX 480 boards was not optimal. Fortunately, we can adjust the GPU's tuning via software in order to resolve this issue. We are already testing a driver that implements a fix, and we will provide an update to the community on our progress on Tuesday (July 5, 2016).

If some of the data is to be believed, these cards are exceeding 150W total at times, which would mean there is either something causing them to run in the wrong power state, or they are just outright exeeding their power limit and need to be throttled back. As we don't do per-rail testing I don't have anything meaningful to add at this second, but it will be very interesting to see how AMD responds next week.

Update 07/06: AMD has since released their status update, which you can find here.

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  • SunnyNW - Saturday, July 02, 2016 - link

    What I meant by it not being apart of the normal reviewing process is that maybe AMD did not expect anyone to catch it or at least not this quickly especially before AIB cards were out. After AIB cards are released I'm sure most people will downplay the issue because I'm sure those will vastly outsell the reference but that does not mean the issue can be ignored.
    I dont see AMD having too many options regarding this issue.
    A) they either power throttle the card costing performance, which will be a Huge negative. I know I for one would probably not keep the card if its going to perform any less because I dont see it beign an insignificant amount. (Hopefully I'm wrong)
    B) They move more current draw from the slot to the 6-pin. In which case the card will still not be compliant with the spec. Even though I admit I for one would not mind this solution knowing how "over-built" those connectors are anyway.
    Reply
  • euskalzabe - Saturday, July 02, 2016 - link

    This. One of the few intelligent answers I've seen so far on this topic. Reply
  • Drumsticks - Saturday, July 02, 2016 - link

    Oddly enough I'm seeing a lot of reports about undervolting the 480 and actually reducing the power draw and increasing performance because the power/temp limit (one of them) was no longer hit. I wonder if it would be possible to do better on efficiency by dropping the voltages at stock. Reply
  • mutantmagnet - Saturday, July 02, 2016 - link

    The Sabertooths are beasts when it comes to power management. You have nothing to worry about. Keep in mind that the PCIE issue exists mostly for anyone using a PCIE 1.0 slot or a cheap modern motherboard. Even though modern mobos use 2.0 and 3.0 slots they can and will cut costs by taking out the feature that allows them to have higher wattage pulled through them.

    AMD made a couple of gross miscalculations for their target audience.
    Reply
  • SunnyNW - Saturday, July 02, 2016 - link

    Thanks. I was just talking with a friend and maybe someone here can also help. Is there any difference between PCIe 2.0 vs 3.0 when it comes to power delivery specifications? I have a friend using AMD 990fx and so has a 2.0 slot and has ordered a reference card, any potential issues he needs to worry about? Reply
  • lmotaku - Saturday, July 02, 2016 - link

    Sorry for the redundancy/typos, no edit button and getting into my morning coffee. lol Reply
  • DanNeely - Saturday, July 02, 2016 - link

    nope. Power delivery has been unchanged since 1.0: 25W as the baseline for everything except 1x low profile and (optionally) 16x cards, consisting of up to 3A @ 3.3v (10W) and/or 2.1A @ 12V (25W). Full height 16x cards can optionally do 75W, made up of up to 3A @ 3.3 V and 5.5A @ 12W (66w). The 3A @ 3.3V part of the spec is a hold over from the legacy PCI days; and was intended to make converting existing designs easier by just adding a PCI-PCIe1x bridge and not requiring any major hardware changes.

    Beyond that there are additional limits in the spec for low profile 1 and 16x cards. Low profile 1x cards, are limited to up to 3A @ 3.3v and up to .5 A @ 12v. Low profile 16x cards are supposed to be limited to 25W. I'm assuming these were added to the spec to allow OEMs to limit the size of the PSUs (and thickness of the copper used in the power planes in the mobo itself) they put in small form factor systems without having to worry about them being overloaded. TTBOMK there's not any way to enforce the lower limits; and I suspect a lot of higher performing low profile cards are massively out of spec. ex The GT 740 has a nominal 64W TDP, while the GT730 and R7 240 (Newegg doesn't list any newer AMD low profile cards) are both above 30W (the 730 by a significant amount). It might have something to do with most of the nVidia cards being from Zotac and other low tier OEMs, if EVGA/MSI/ASUS/etc weren't willing to risk the wrath of the spec committee gods by violating the spec that severely.
    Reply
  • StrangerGuy - Saturday, July 02, 2016 - link

    So what you are saying is, it's the mobo manufacturers responsibility to overspec their boards so they can accommodate the out-of-spec PCIE power draw of the RX 480?

    Did you even think about how ridiculous you sound?

    How about if somebody runs over your car with a tank and he says "lol, your fault for not using an armored vehicle"?
    Reply
  • coder543 - Saturday, July 02, 2016 - link

    The way mutantmagnet phrased it is rather strange, so I won't defend his statement, but yours is also ridiculous. In engineering, you *never* design things to precisely meet the spec. If you do, your work is destined to fail. You have to overengineer things by some margin, a safety buffer, for exactly when weird things happen, which they will. "Defensive design" is one term for it.

    It doesn't justify AMD using the safety margin for their own ends, and they're planning to roll out a software update to fix this issue by the sounds of things, but it is unlikely to actually damage any but the cheapest of motherboards.
    Reply
  • Morawka - Sunday, July 03, 2016 - link

    if you call the Asrock Extreme Gaming4 a cheap motherboard then ok.. that's a top tier AMD board and 3 people so far have burnt pci-e slots Reply

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