Radeon RX 480: PCIe slot power draw issue

[Bikerdude]

As some one(OldJim/Nbohr1more) recently pointed out, the RX 480 is pulling more power over the PCIe port than the specification allows. This is bad -

• Pulling more than 75 from the PCIe socket can possibly damage or reduce the life of your motherboard.
• According to the licensing contract for the spec, if AMD do not fix this within 3 months they will NOT be able to call the card a PCI Express card. If they do, they face not only litigation but a ban the importation of the card as counterfeit.
• AMD are stating inconsistent facts, the card was marketed as having a TDP of 150W, now their saying the GPU uses 110W. Yet a bunch of reviews have measure card pulling upto 175w and beyond.

So did a google search on the issue -

• https://www.reddit.com/r/Amd/comments/4qfwd4/rx480_fails_pcie_specification/?st=iq2gakwz&sh=4ad76483
• http://www.tomshardware.com/reviews/amd-radeon-rx-480-polaris-10,4616-9.html
• http://www.pcinvasion.com/amd-looking-rx480-pcie-compliance-failure-reports
• http://asidcast.com/amd-screws-up-as-rx-480-fails-pci-e-specifications-what-does-this-mean-for-gamers/

Looks like some reviewers are getting cards the public would never see which in itself is something to be concerned about. AMD stated, this as due to some cards that were sent out were dual bios so reviewers could test 4Gb and 8GB configurations of the card. Overclockers UK have said they sold over 1000 RX 480's already, I wonder how many of these will get returned and how many of these will result in dead motherboards/lawsuits.

 

All in all, this is an own goal for AMD, as it is it looks like it only effects Reference cards with 6pin PCIe power connectors(which is all of them atm). I imagine 3rd party venders will eventually start shipping card's with custom coolers and 8pin power connectors. The only card I ever bought with a reference cooler is my old HD 5870 which SirTaff now owns (that card never loud even under full load) But since then and due to the lack of any descent & cost effect 3rd party coolers these days, I just buy cards with 2 or 3 fans on.

[Bikerdude]

Well been reading up a bit more about this -

• https://www.reddit.com/r/Amd/comments/4qmlep/rx_480_powergate_problem_has_a_solution/

The PCI-E 3 specifications regarding the 75 watt limit. isnt the maximum limit- its just the default value on startup of the motherboard. The motherboard it self sets the maximum allowed watt per slot, which can be upto 300 watts

The issue I have with that statement, is when was the last time anyone saw in a user manual or on the manufactures website - the max power listed for the PCIe slots on a motherboard. So then went to the source thread -

• https://www.reddit.com/r/pcmasterrace/comments/4qfy9d/i_work_at_amd_the_time_has_come_to_ama_about/d4tksww

Basically the protocol seems to allow more power draw but the electro mechanical part limits it. It says indeed that the power must not exeed the limit of 75 watt

Then more digging on the subject of power being pulled over the PCIe slot, show some other cards pulling more than the PCIe spec allows for -

• GTX 750ti - https://forums.overclockers.co.uk/showpost.php?s=000e390144d365c5df4da576266d5a5e&p=29719806&postcount=7
• GTX 960 - http://videocardz.com/61667/what-reviewers-say-about-radeon-rx-480-exceeding-pci-express-power-specifications

But then another review of a GTX 970 and 980 both working within spec -

• http://www.tomshardware.co.uk/nvidia-geforce-gtx-980-970-maxwell,review-33038-12.html

bah...

[jaxa]

AMD loses in power efficiency yet again.

[Bikerdude]

Well no, the 480 is cometing directly with the 970 at a lower price and power point.

 

And here is an intelligent and considered review that came to pretty much the same conclusion I have - Don't buy a reference designed 480 with a 6pin connector (and who in their right mind buys a gfx card with a reference cooler these days....)

 

[Oldjim]

AMD appear to be dodging the fundamental problem https://www.techpowerup.com/223833/official-statement-from-amd-on-the-pci-express-overcurrent-issue?

 

AMD sent us this statement in response to growing concern among our readers that the Radeon RX 480 graphics card violates PCI-Express power specification, by overdrawing power from its single 6-pin PCIe power connector. Combined with the PCI-Express slot, the total power budged of the card should be 150W, however, it was found to draw well over that power limit.

AMD has had out-of-spec power designs in the past with the Radeon R9 295X2, for example, but that card is targeted at buyers with reasonably good PSUs. The RX 480's target audience could face troubles powering the card. Below is AMD's statement on the matter. The company stated that it's working on a driver update that could cap the power at 150W. It will be interesting to see how that power-limit affects performance.

"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 8 Gbps 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)."

 

 

[Oldjim]

seems to be sorted http://www.tomshardware.com/reviews/amd-radeon-rx-480-polaris-power-fix,4668.html

but I would still wait for one with an eight pin PCIe connector

Edited July 9, 2016 by Oldjim

[Bikerdude]

Yes, a 3rd party vendor with better cooling aswell.

[Oldjim]

Lots of third party vendors with better cooling and 8 pin connectors now available albeit still a bit expensive

[Bikerdude]

now available albeit still a bit expensive

Shop around, I bet cheaper than std priced can be found.