AMD Radeon RX 480 Power Measurements Repeated And Clarified

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ssdpro

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"Summary
1. Our modified second round of measurements replicated the results of our first round. The amount of current flowing through the motherboard PCIe slot’s 12V rail exceeds the upper limit of the tolerance range described in the PCI-SIG specifications. Our repeated measurements of the reference card show currents 23 percent above the PCI-SIG norm."

So, the summary was the same. The new article just puts more emphasis on the minimal risks/dangers than the compliance failure itself. Seems like an attempt to please someone, or appease some source of revenue.
 

FormatC

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Totally wrong. Not only the summary is the same, the results are also totally similar. And exactly this is the difference to a lot of other re-benches I saw after the launch. I got a lot of feedback about our measuring methods and also had to read a lot of crap and allegations on other sites and forums. This was the reason why I simply does the same: low-res measuring, even more low-pass-filtering and enlarged pictures. Funny: nothing has been significant changed. This few spikes goes mostly in both directions, so you have the same average as cutted or smoothed curves (different choise).

The new article just puts more emphasis on the technical background, possible reasons and the math behind if it's allowed to correct you with my own words :)

The goal was to find the reason for the results and to be honest: my family lost the whole weekend with me and I lost over two days of my lifetime. That means: I does it not for my pleasure but I feel it's only fair to our readers to clarify something. :)

And finally to be accurate: This is only a question of current, the power consumption is secondary. ;)
 

Placobravo

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I wonder if they could simply solve this by a driver update, so that the card could function as any other card (which means taking most of the power from the 6-pin connector rather then the PCI-E).
Anyway at this point it is clear to me that anybody wishing for an rx-480 should wait for aftermarket solution. Brands like Sapphire will definitely solve those issues :)
 

frzsk

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Specifications covering just how much power is allowed to flow through the pins of a 16x PCIe motherboard slot were established a long time ago. However, saying that they include a maximum wattage isn’t just misleading, but flat out false.

The PCI-SIG defines the maximum amperage for the 12V motherboard slot connector as 5.5A, with a maximum tolerance for voltage of plus or minus eight percent (see table below). A quick multiplication of this number by 12V yields either the reference point of 66W, or the maximum of 71W that includes the eight percent.

EDIT:

You say in the first paragraph that there's no max wattage but in the 2nd paragraph you say that there is one.
 

FormatC

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The protocoll, used by their PWM controller allows a re-balancing and it is in theory also possible to supply the whole card with only two of this oversized phases :)
I'm sure they will move a little bit more load to the 6-pin PCIe, beacuse he is completely connected. My own tests showed that they will survive 300 watts and more without damage.



This is exactly what I wrote on top of page Two. Only the current is interesting, the voltage is within the ATX specs and a completely other story. The translation from German is not clear enough - in original I wrote, that this wattage product is used from the masses to simplify the problem but it is totally unusual ;)

I wrote this also to our editor-in-chief and hope that he can fix it asap. Thx for finding. ;)
 

JRHERITA

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This is bad - because over time that 23% spec will be harder and harder on the motherboard components. A chip that runs hotter consumes more power -- and an older GPU will certainly run hotter due to a less than perfectly clean case/GPU fan setup, the transistors aging (perhaps needing more voltage to work causing power to go up). On top of this, the motherboard connectors don't stay pristine forever, nor do the motherboard power circuits or even the power supply. Being overspec may work OK now, but in a few years, that's not so certain.
 

gorgamin

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A real Electrical Engineer has answered some of the myths reviewers have been propagating. I think most of these reviewers need to go back to EE school (incl. Tomshardware) as they don't seem to grasp what they're saying.

There is nothing wrong with the RX480
https://www.reddit.com/r/Amd/comments/4rbw8p/facts_about_pcie_connectors/
 

cilliers

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Tomshardware very seldom replicates experiments for the same product, so therefore this article looks really out of place. As I was reading this second article , I couldn't help imagining an angry AMD marketing man on the phone with the TH editor, demanding at least a second round of tests with a newly shipped card. This is so funny, especially the 6 points listed for clarification in the summary. By the way. "Assumptions" to an experiment always go in the paragraph about the experiment design, not at the back...FYI. This is just too funny. Thank you TH.
 

FormatC

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Ok, so the PCIE-SIG is wrong and a nursery... As I wrote: to be comparable to (older) hardware. Send this engineers's comedy to someone from the SI business, he will hit you :D

Tomshardware very seldom replicates experiments for the same product, so therefore this article looks really out of place.
Also wrong. They very seldom translated my content from German. To be honest: AMD is not paying for my pleasure or some sexual services. :D

Also funny: yesterday I was totally Nvidia-biased, today I'm AMD biased. So what? :p

 

Biscuit42

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My view still holds: This isn't an issue with the Polaris GPU, it's an issue with the rock-bottom, bare minimum Reference cards AMD released. The reference cards are not suitable for overclocking.

I suspect they did this to allow their board partners the opportunity to come out with 8-pin boards that overclock well.
 

FCsean

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No problem. I was actually lost for a few seconds there as to what you really meant there.
 

FormatC

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This isn't an issue with the chip, right. And if you change a few zero-ohm-resistors (bridges) on the PCB you will get a better balanced card that need an 8-pin connector to keep the standard. For AMD it was only a psychological fact to show a card with only one 6-pin connector - to suggest efficiency and power saving. It's marketing, not engineering. This is the only one issue that AMD made.

 

phux303

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Think your card is running with voltages set too high, have toms hardware spent any time faffing about with these for a potential solution?, many people are reporting much lower values than you posted in your original review, saving many watts and even increasing performance, amd release info soon and possible fix, am interested in toms followup, for sure the custom boards will be better and this will be a distant memory
 

FormatC

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I've also tried to undervolt it, but I lost a lot of performance (clock speed). It seems we can found a lot of various chip qualities and AMD pushed the voltage to increase the yield rate a little bit. I saw other cards working at 1.05V.

 

jimmysmitty

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And I think most Electrical Engineers need to stop thinking just because they are engineers that they know more than people who have been in the computer industry for 20+ years. Some of the worst people to deal with on computers are EEs. Last one I dealt with knew more than I did about PCs yet couldn't figure out why his PC wouldn't boot.

That said, I trust the PCE-SIG and Toms over come random guy on reddit.



It is a good thing that Toms doesn't rely on AMD for revenue. I could imagine they were not too happy about it because it has caused quite a storm.



Maybe, mabye not. It could be a BIOS issue.

And the second part would be stupid. Why would you risk anything just for that?



There is a pretty interesting thing we overclockers use called the silicon lottery. When I got my Q6600 G0, most people were getting 3GHz on stock voltage. I however was able to get 3GHz on less than stock voltage. I won the silicon lottery with that chip. Not everyone will have the same success so it is not a 100% viable solution and for some people they might lose performance with a lower voltage.

It is better to wait for AMDs fix. The other thing is it is always better to wait for AiB boards anyways as they typically are designed to have a higher power draw.
 

kiniku

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Maybe not that big of a deal and it reminds me of the GTX970 memory fiasco but the truth is AMD really didn't need this. Most people were hoping for a flagship that was comparable to Nvidia's 10 series release, regardless of timetables.
 

FCsean

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Well those people don't make up around 80+% of the gamers that can only afford to buy a card around 100-300$.
 

FormatC

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To understand me right guys:

I respect this product and it is one of the best deals for this price point. I also will use one of those cards in my sons PC but what I absolutely hate: if a company doens't respect their own products and engineers but let the marketing guys make such totally unnecessary mistakes like this. Where the hell is the problem with an 8-pin?

AMD has a big fan base and needs money. Everybody will respect the truth - but for AMD it's a problem to see the truth in the face. Just my very private, not official 50 cents :)


It is worse, if a board partner sells an 700 Euro++ VGA card and simply forgot the hysteresis for the fans. This is even worse :D
(found it today on a "high-end" 1080 flagship product when I controlled the PWM signals)

I worked so many years for the industry and moved only four years ago to the media. And I really know the difference between engineering and marketing. The engineers created a good product that was killed by marketing issues. Too many eggheads in suits and too many overzealous accountants are able to kill each company faster than you can say pug. :D
 

IceMyth

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I think this article is a bit late, as AMD admitted it might happen with very rare old MB. But also they said they will push a fix in the Radeon update as this is not a hardware issues rather than software!
 

FormatC

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To be honest: I'm standing in contact with AMD and not one of the technical side wrote me something similar. I compared the PCB with a retail card and saw no difference. same PCB, same bridges, same results.I also wrote about the opportunities of the used PWM controller to re-balance the system "on-the -fly". Please read the article more carefully, especially the intro with AMD's quote. ;)



 

Onemoar

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Umm wait just a second TOM's
most of the VCORE comes from the 6 pin and not the PEG slot so you made a major faux-pas there
the 6 Pin feeds the main VCORE stage and nothing else

the PEG slot feeds the RAM and the AUX line which is used for low-power states

AMD's 6 Pin is wired a bit weird all 3 pins are direct grounds instead of sense so you can indeed pull 150W over it
 

FormatC

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I'm sure, you can explain this in detail. This is the normal way but needs an 8-Pin. 80 watts for memory, as we measured, are simply too much. Follow the rails on the PCB and take a look at all this soldererd bridges (zero ohm resistors). ;)
 
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