AMD RX 480 Fails PCI-E Specification

Biffa · 7 Jul 2016 at 20:07

Pcie = 6pin Pcie power plug
Main board 12V = power drawn through the Pcie slot via the motherboard.

Hope that clarifies things.

Basically even with compatability mode off it draws less power through the Pcie slot.

hominid · 7 Jul 2016 at 20:08

PCIe 12v is the lead from the power supply, mainboard 12v is from the motherboard - ie, throught the PCIe connector.

TheRealDeal · 7 Jul 2016 at 20:08

What it also shows is you don't even need this new compatibility mode on with the new driver. It's only pulling 72W without the new mode on the new driver and you are gaining clock speed while at it. So performance should be slightly up while being within the PCI-E spec. Job well done if this holds true but it looks good atm.

Zhuni · 7 Jul 2016 at 20:09

Ahh thanks guys. I thought pcie meant power through the pcie. Well that's good news then.

Rovman · 7 Jul 2016 at 20:12

Yeh, i think people are confused as to what the compatibility mode was for. Think of it this way.

Installing the driver (and making no settings changes) fixes the power draw issue and gives ~3% increased performance.
Compatibility mode is a further option to reduce power even more at the cost of a slight hit in performance vs the older drivers, however the 3% increase from these drivers partially (maybe fully) offsets that.

Also remember the 6 PIN connector on the RX 480 is actually an 8 pin in terms of capability, providing 3x 12v and 3 x Grnd wires, as opposed to 6 pin spec which would be 3x12v + 2x Grnd + 1xsense.

D.P. · 7 Jul 2016 at 20:13

N19h7m4r3 said:
How did they? The PCIe Slot/Motherboard draws less power, which was the issue. 68 vs original 82.

That power draw was redirected to the PCIe-PowerSupply connector.

The 6pin PCI PSU connect also has a 75w limit, the drivers do indeed push this further out of spec which is not great but less of an issue than the motherboard PCI slot draw.

The comparability mode is the onyl true fix to get the card closer to specifications but I expect everyone except with the old and cheap PSUs will get by with the new drivers. The thing is, if AMD are marketing the 480 as a budget card then there are bound to be people out there with lousy PSUs trying to run the card and the PSU wont be that happy with 93w over the 6 pin.

Jono8 · 7 Jul 2016 at 20:15

Those clock rates on the compatibility mode look a bit rubbish and very erratic. Not sure why you would use it consdering you are only saving 9 watts.

TheRealDeal · 7 Jul 2016 at 20:17

D.P. said:
The 6pin PCI PSU connect also has a 75w limit, the drivers do indeed push this further out of spec which is not great but less of an issue than the motherboard PCI slot draw.

The comparability mode is the onyl true fix to get the card closer to specifications but I expect everyone except with the old and cheap PSUs will get by with the new drivers. The thing is, if AMD are marketing the 480 as a budget card then there are bound to be people out there with lousy PSUs trying to run the card and the PSU wont be that happy with 93w over the 6 pin.

There is people out there trying to run high end cards on sub standard psu's. People often don't understand the importance of a good psu. They only look at the wattage number and cheap out. There has been plenty of posts over the years in this section to prove it.

Angilion · 7 Jul 2016 at 20:18

TheRealDeal said:
What it also shows is you don't even need this new compatibility mode on with the new driver. It's only pulling 72W without the new mode on the new driver and you are gaining clock speed while at it. So performance should be slightly up while being within the PCI-E spec. Job well done if this holds true but it looks good atm.

Yes...but then it's pulling 93W through the 6-pin PCI-E connector, which is specced for 75W.

That shouldn't be a real problem in practice because in practice they're usually rated well over spec, but it's clearly out of spec and thus a bit dodgy.

This is not the 150W card AMD claimed it was and therefore making it with a single 6-pin connector is wrong and marketing it as a 150W card is wrong.

An RX 480 with a 8-pin connector (or 2 6-pin) and which pulls <75W through the PCI-E slot is something I might buy. I don't care that it's a 170W card and the amount that I care about AMD lying about the power draw isn't enough to stop me buying one. But a reference card? No. They're made wrong.

D.P. · 7 Jul 2016 at 20:20

TheRealDeal said:
What it also shows is you don't even need this new compatibility mode on with the new driver. It's only pulling 72W without the new mode on the new driver and you are gaining clock speed while at it. So performance should be slightly up while being within the PCI-E spec. Job well done if this holds true but it looks good atm.

Apart from the 6pn connector being out of spec.

N19h7m4r3 · 7 Jul 2016 at 20:20

Angilion said:
An RX 480 with a 8-pin connector (or 2 6-pin) and which pulls <75W through the PCI-E slot is something I might buy. I don't care that it's a 170W card and the amount that I care about AMD lying about the power draw isn't enough to stop me buying one. But a reference card? No. They're made wrong.

Yup, I completely agree. Then again when was the last decent Reference air cooled cared from AMD? It's been years now, and thank goodness their board partners are top notch.

The Sapphire Nitro 480 is the one to buy if you want a proper 480.

Jono8 · 7 Jul 2016 at 20:22

D.P. said:
The comparability mode is the onyl true fix to get the card closer to specifications but I expect everyone except with the old and cheap PSUs will get by with the new drivers. The thing is, if AMD are marketing the 480 as a budget card then there are bound to be people out there with lousy PSUs trying to run the card and the PSU wont be that happy with 93w over the 6 pin.

That is true. Im surprised they couldnt get something with this level of performance within spec (<150w).

RavenXXX2 · 7 Jul 2016 at 20:26

Angilion said:
Yes...but then it's pulling 93W through the 6-pin PCI-E connector, which is specced for 75W.

That shouldn't be a real problem in practice because in practice they're usually rated well over spec, but it's clearly out of spec and thus a bit dodgy.

This is not the 150W card AMD claimed it was and therefore making it with a single 6-pin connector is wrong and marketing it as a 150W card is wrong.

The 6 pin is wired like an 8 pin, all the power the card needs is there no issues at all. 480 is doing big sales, all sold out on newegg, AMD market share up 10%.

N19h7m4r3 · 7 Jul 2016 at 20:27

Jono8 said:
That is true. Im surprised they couldnt get something with this level of performance within spec (<150w).

Probably could if they cut out all the compute power from the cards, such as what happened with Maxwell and Pascal.

Biffa · 7 Jul 2016 at 20:28

The 6 pin pcie plug has been specced to 150W since pcie2.0 specs changed in 2007
http://www.tomshardware.co.uk/forum/274631-28-power-spec-power-plug

D.P. · 7 Jul 2016 at 20:29

TheRealDeal said:
There is people out there trying to run high end cards on sub standard psu's. People often don't understand the importance of a good psu. They only look at the wattage number and cheap out. There has been plenty of posts over the years in this section to prove it.

People continue a high end expensive GPU to a cheap PSU are just being stupid. Even then, if someone buys a GPU and has PSU within the requirements there is a pretty minimal chance of issues.

People connecting a RX480 to a cheap PSU probably don't know much better and are on a budget. Without realizing it they have a system outside the expected specifications. I don't think that is a catastrophe but as Anglion says, the RX480 is not a 150w card and should never have been put on a PCB designed for 150w. It is a 170w card, should be marketed as that and should only be sol in configuration that can supply 170w without going outside specifications.

the reference RX480 really need a recall and to be removed form the shelves. The solution is simple, a beefed up reference PCB with an 8pin connector and for AMD to stop pretending they have an efficient card.

D.P. · 7 Jul 2016 at 20:30

N19h7m4r3 said:
Probably could if they cut out all the compute power from the cards, such as what happened with Maxwell and Pascal.

Polaris also has 64bit compute stripped out, as does Fiji.

Hotwired · 7 Jul 2016 at 20:35

D.P. said:
the reference RX480 really need a recall and to be removed form the shelves

Go on then, make the legal claim if you've got some substance.

There's one guy out there who thinks the 480 did him wrong, you can use him as a witness.

D.P. · 7 Jul 2016 at 20:37

Hotwired said:
Go on then, make the legal claim if you've got some substance.

There's one guy out there who thinks the 480 did him wrong, you can use him as a witness.

Why should I make a legal claim, got nothing to do with me. I wouldn't go anywhere near an RX480

Rroff · 7 Jul 2016 at 20:46

D.P. said:
but as Anglion says, the RX480 is not a 150w card and should never have been put on a PCB designed for 150w. It is a 170w card, should be marketed as that and should only be sol in configuration that can supply 170w without going outside specifications.

Yup.

The extra current over the 6 pin connector is a non-issues though as realistically if your PSU/wiring has trouble with that then the 480 is the least of the issues you should be worried about with your PC heh. There should be considerable margin there even on the cheapest and crappiest PSUs.