AMD RX 480 Fails PCI-E Specification

N19h7m4r3 · 30 Jun 2016 at 19:27

D.P. said:
Drawing more power over a sustained period isn't great but you have to realize the 75w is actually the minimum, not maximum rating. Its not the end of the world but AMD should have just gone with an 8pin.

I completely agree with this. It might not have looked good PR wise, but this scenario looks worse with all the severe negative spin on it.

It's really a none issue; the real issue for me is the heat and performance per watt. Seems Global Founderies process ain't ass nice as TSMC's 16nm version, as the shrink to 14nm should really have done a better job at thermals and power needs.

RavenXXX2 · 30 Jun 2016 at 19:28

D.P. said:
Bigger issue is the card seems to pull around 160-170w when gaming which is pretty atrocious for the performance and on 14nm. these things are clocked well beyond the reasonable clock-power curve.

Got to agree, when your 14nm part is drawing the same power as Nvidia's 28nm 970, somethings gone wrong.

Orangey · 30 Jun 2016 at 19:32

drunkenmaster said:
I also like the thread title, seeing as AMD apparently sent the card to PCI-e who tested and certified it... thus it didn't fail PCI-E specs.

This has already been debunked, the sample they sent for testing was using a different BIOS.

Silent_Scone · 30 Jun 2016 at 19:42

Not only that, but apparently everyone is an electrical engineer. There are tolerances in all these specifications.

D.P. · 30 Jun 2016 at 19:44

Silent_Scone said:
Not only that, but apparently everyone is an electrical engineer. There are tolerances in all these specifications.

Which is why i said the PCIE 75W rating is actually a minimum not a maximum.

Silent_Scone · 30 Jun 2016 at 19:48

D.P. said:
Which is why i said the PCIE 75W rating is actually a minimum not a maximum.

lol is it now

Gregster · 30 Jun 2016 at 19:49

D.P. said:
Which is why i said the PCIE 75W rating is actually a minimum not a maximum.

No DP, it isn't at all the minimum.

sand_dune · 30 Jun 2016 at 19:57

You can never defeat Nvidia fans with arguments. They will use their own illiteracy to come at you in great numbers and scream at you that you should have bought none other than Nvidia card.

I bet there will not be apologies or retractions from all the websites that published this nonsense, when from the first sight it is clear that PCIE allows far more than 75w from socket more like 300w.

ihatelag · 30 Jun 2016 at 19:58

Is the card is exceeding the official TDP?

Stanners · 30 Jun 2016 at 20:00

sand_dune said:
You can never defeat Nvidia fans with arguments. They will use their own illiteracy to come at you in great numbers and scream at you that you should have bought none other than Nvidia card.

I bet there will not be apologies or retractions from all the websites that published this nonsense, when from the first sight it is clear that PCIE allows far more than 75w from socket more like 300w.

You can put 300watts through the PCIE?

FoxEye · 30 Jun 2016 at 20:00

D.P. said:
Drawing more power over a sustained period isn't great but you have to realize the 75w is actually the minimum, not maximum rating. Its not the end of the world but AMD should have just gone with an 8pin.

Bigger issue is the card seems to pull around 160-170w when gaming which is pretty atrocious for the performance and on 14nm. these things are clocked well beyond the reasonable clock-power curve.

Is it tho (a minimum).

From the Reddit thread (quoting whole post):

The power usage etc. is defined in the PCI Express Card Electromechanical Specification. Please look at page 27 and 36 of the PCI Express® Base Specification Revision 3.0

From Page 27 "Document Organization"

"The PCI Express Base Specification contains the technical details of the architecture, protocol, Link Layer, Physical Layer, and software interface. The PCI Express Base Specification is applicable to all variants of PCI Express.
The PCI Express Card Electromechanical Specification focuses on information necessary to implementing an evolutionary strategy with the PCI desktop/server mechanicals as well as electricals. The mechanical chapters of the specification contain a definition of evolutionary PCI Express card edge connectors while the electrical chapters cover auxiliary signals, power delivery, and the adapter interconnect electrical budget."

Page 36 states the Reference Documents and the PCI Express Card Electromechanical Specification

And from the PCI Express™ Card Electromechanical Specification Rev. 1.1 (2.0 is behind a paywall, but wikipedia has the same information):

"A standard height x16 add-in card intended for server I/O applications must limit its power dissipation to 25 W. A standard height x16 add-in card intended for graphics applications must, at initial power-up, not exceed 25 W of power dissipation, until configured as a high power device, at which time it must not exceed 75 W of power dissipation. Refer to Chapter 6 of the PCI Express Base Specification, Revision 1.1 for information on the power configuration mechanism."

Griffildur · 30 Jun 2016 at 20:01

sand_dune said:
You can never defeat Nvidia fans with arguments. They will use their own illiteracy to come at you in great numbers and scream at you that you should have bought none other than Nvidia card.

I bet there will not be apologies or retractions from all the websites that published this nonsense, when from the first sight it is clear that PCIE allows far more than 75w from socket more like 300w.

don't worry you can keep your AMD card and I can guarantee you that no one really cares

sand_dune · 30 Jun 2016 at 20:01

ihatelag said:
Is the card is exceeding the official TDP?

That's not even a legitimate question. There's hardly an official tdp. Usually official TDP is just an approximate number. And reviewer test what the card draws for real.

No it doesn't

melmac · 30 Jun 2016 at 20:03

This is nonsense of the highest order. Is it really gone that bad in the GPU world that people would believe this? Cards have been going way over the Pcie spec for years, the 6990 for example. Mind you the same rubbish was been spouted back then too.

Here is a snippet from Anandtech about the 6990.

So what does the PCI-SIG think about cards such as the 6990 which exceed the PCIe specification? In a nutshell, they don’t directly care. The group’s working philosophy is closer to approving cards that work than it is about strictly enforcing standards, so their direct interest in the matter is limited. The holy grail of the PCI-SIG is the PCI Express Integrators List, which lists all the motherboards and add-on cards that have passed compliance testing. The principal purpose of the list is to help OEMs and system integrators choose hardware, relying on the list and by extension PCI-SIG testing to confirm that the product meets the PCIe standards, so that they can be sure it will work in their systems.

The Integrators List is more or less exclusively OEM focused, which means it has little significance for niche products such as the 6990 which is split between end-user installation and highly customized OEM builds. The 6990 does not need to be on the list to be sold to its target market. Similarly the 5970 was never submitted/approved for listing, and we wouldn’t expect the 6990 to be submitted either.

It is worth noting however that while the PCI-SIG does have power specifications, they’re not a principal concern of the group and they want to avoid doing anything that would limit product innovation. While the 300W specification was laid out under the belief that a further specification would not be necessary, the PCI-SIG does not even test for power specification compliance under their current compliance testing procedures. Conceivably the 6990 could be submitted and could pass the test, leading to it being labeled PCIe compliant. Of course it’s equally conceivable that the PCI-SIG could start doing power compliance testing if it became an issue…

At the end of the day as the PCI-SIG is a pro-compliance organization as opposed to being a standard-enforcement organization, there’s little to lose for AMD or their partners by not being compliant with the PCIe power specifications. By not having passed compliance testing the only “penalty” for AMD is that they cannot claim the 6990 is PCIe compliant; funny enough they can even use the PCIe logo (we’ve already seen a Sapphire 6990 box with it). So does PCIe compliance matter? For mainstream products PCIe compliance matters for the purposes of getting OEM sales; for everything else including niche products like the 6990, PCIe compliance does not matter.

sand_dune · 30 Jun 2016 at 20:05

Stanners said:
You can put 300watts through the PCIE?

250-300w yes, few people know it as it seems. I didn't know. But I made just a little research that anyone can do and I see that that is the truth.

melmac · 30 Jun 2016 at 20:07

FoxEye said:
Is it tho (a minimum).

From the Reddit thread (quoting whole post):

It's a made up spec from years ago before anybody thought cards would ever use 300w never mind more than 300w.

Stanners · 30 Jun 2016 at 20:08

sand_dune said:
250-300w yes, few people know it as it seems. I didn't know. But I made just a little research that anyone can do and I see that that is the truth.

Yeah I just had a read and it states F2h - 300 w slot power limit. Is this something to do with high power PCIE slots. I will have to read more

ihatelag · 30 Jun 2016 at 20:10

sand_dune said:
That's not even a legitimate question. There's hardly an official tdp. Usually official TDP is just an approximate number. And reviewer test what the card draws for real.

No it doesn't

OK - I have checked and YES it has exceeded it. It's what AMD have said on their advertised card. How much more official can it be? It's taking it much further than advertised.

FoxEye · 30 Jun 2016 at 20:11

Stanners said:
Yeah I just had a read and it states F2h - 300 w slot power limit. Is this something to do with high power PCIE slots. I will have to read more

As I quoted a couple posts above, it would appear that there are two spec documents. One which mentions 300W, and one which mentions 75W.

Which of those two spec documents apply to PCI-E gfx cards would appear to be a thing of contention atm.

I won't claim to know

N19h7m4r3 · 30 Jun 2016 at 20:13

FoxEye said:
As I quoted a couple posts above, it would appear that there are two spec documents. One which mentions 300W, and one which mentions 75W.

Which of those two spec documents apply to PCI-E gfx cards would appear to be a thing of contention atm.

I won't claim to know

75W for Spec 1.1, the higher ratings for for 2.1 and above from what I saw in the links.