AMD Details Driver Fix For Radeon RX 480's Controversial, Spec-Exceeding Power Draw (pcworld.com)

AMD's 150-watt Radeon RX 480 apparently draws more power than it is supposed to. According to Tom's Hardware blog, AMD's new graphics card used an average of 168W under load. Furthermore, the publication found that card pulled up to a whopping 90W over the motherboard's PCI-E slot, far exceeding the 75W maximum the slot it rated for. PC Perspective's findings were similar, with Witcher 3 title consuming over 190W of sustained power draw when the RX 480 was overclocked. Worse, the blog discovered that AMD's card drew 7 amps over the PCI-E slot's +12v rail, which is rated for 5.5 amps maximum. These issues could theoretically (but not likely) damage lower-end motherboards in extreme circumstances, writes PCWorld. The chip company last week addressed the concerns, noting that it will soon release a software fix. In a new statement to PCWorld, the company adds:"We promised an update today (July 5, 2016) following concerns around the Radeon RX 480 drawing excess current from the PCIe bus. Although we are confident that the levels of reported power draws by the Radeon RX 480 do not pose a risk of damage to motherboards or other PC components based on expected usage, we are serious about addressing this topic and allaying outstanding concerns. Towards that end, we assembled a worldwide team this past weekend to investigate and develop a driver update to improve the power draw. We're pleased to report that this driver -- Radeon Software 16.7.1 -- is now undergoing final testing and will be released to the public in the next 48 hours. In this driver we've implemented a change to address power distribution on the Radeon RX 480 -- this change will lower current drawn from the PCIe bus. Separately, we've also included an option to reduce total power with minimal performance impact. Users will find this as the "compatibility" UI toggle in the Global Settings menu of Radeon Settings. This toggle is "off" by default. Finally, we've implemented a collection of performance improvements for the Polaris architecture that yield performance uplifts in popular game titles of up to 3%. These optimizations are designed to improve the performance of the Radeon RX 480, and should substantially offset the performance impact for users who choose to activate the "compatibility" toggle.

Comments

Take the PCIe logo off the box

[CajunArson]

These cards may or may not damage your motherboard, but there is zero doubt that in the default configuration -- not some out of spec hacked BIOS configuration -- they are not compliant with the PCIe standards.

Putting that PCIe logo on the box is therefore deceptive marketing and AMD should be held accountable here.

Re:Take the PCIe logo off the box

[CajunArson]

The new drivers in the default configuration are still out of spec with PCIe.

The fix that AMD applied is to route more power from the 6-pin PCIe power cable to reduce the power drawn from the motherboard. The motherboard is now supposed to be in-spec (of course, independent testing is necessary) but by defintion the 6-pin PCIe cable, which was already providing more than the specification-rated 75W, is definitely out of spec.

Now as a practical matter, the extra power draw through the 6-pin cable will not cause problems with any halfway decent PSU. However, just saying "oh it won't damage your computer in a practical scenario" is not the same thing as complying with the PCIe specification. Actual compliance with PCIe is required to show the logo on the box and advertise compatibility.

The fact that there is now going to be a non-standard "optional" mode that complies with PCIe is nice, but unless it's the default mode out of the box, it's not enough.

Re:Take the PCIe logo off the box

[sexconker]

You're wrong again. The RX 480 uses the 6-pin cable as an 8-pin cable. It ignores the sense pin and uses it as a ground, which is how it is wired. This gives 3 pairs and allows you to pull as much as an 8-pin while still being in spec with regards to power draw, though out of spec with regards to implementation.

It's completely safe. It's not the first card to draw past spec on the 6-pin or 8-pin cables, and it won't be the last.

If you look at 6+2 pin cables on PSUs, you'll see that the +2 pins are simply extensions of the 6-pin plug. You're not getting more physical pairs in those 6+2 pin cables, yet you're drawing up to twice the current! OUT OF SPEC!!! DOOM AND GLOOM!!! Oh wait, it's completely fine.

Read the specs and look at the physical implementations.

So...

[beelsebob]

So it's going to draw to much directly from the PSU instead then?

I mean, if the default mode doesn't reduce overall power draw, but it does reduce draw from the motherboard, that means it must increase draw from the 6 pin PCIe connector. If the card can draw up to 190W, and only 75W of that is coming from the motherboard, that means 115W is being drawn over a 6 pin PCIe connector which is only designed to have 75W pulled from it. I fully expect the issue to simply move from burned out motherboards to burned out power supplies.

Thanks, early adopters!

[gfxguy]

Without you, I'd end up buying unfixed crap like this! And at full price, too!

It is hard to imagine that AMD missed this...

[FlyHelicopters]

AMD has smart people working for them, how they missed this and launched the card I'm at a loss to explain...

Unless they didn't miss it and hoped no one would notice... Or the left hand didn't talk to the right hand...

As for the extra power coming from the 6-pin PCI-E connector, that doesn't bother me so much, most modern power supplies can do that just fine.

I said *most*, some won't be able to, this is indeed a problem, but for most people the fix is just to update the drivers and the few that it isn't, to put it in "compatibility mode"

The problem is, the people who need *compatibility mode* are exactly the people who won't know that and won't do it.

I think it is a mistake to not make compatibility mode the default and let people manually adjust to the higher draw mode.

Re:It is hard to imagine that AMD missed this...

[Anonymous Coward]

they didn't miss anything
this is one of those cases where the spec is wrong
you CAN safely draw 100W from the PEG slot
you CAN safely draw 170W from a 6Pin (worst case crappiest psu on the planet scenario)

every single high end card on the market takes the PCI-e spec and throws it out the window frankly

the issue was blown out of proportion by a few users that knew nothing of which they spoke and stated it as fact

Re:Does the software update effects performance?

[EndlessNameless]

Burned out PSUs instead of motherboards, here we come!

Exceedingly unlikely. The excess power draw through the motherboard was already being fed by the PSU.

Most PSUs have a single 12V rail that supplies all components in the system, including the motherboard.

As a result, the 12V rail is typically rated to supply most of the PSU's wattage. I would expect no issues unless the total system draw is near the PSU's capacity.

E.g., I have a 400W Seasonic PSU that can supply ~350W on the 12V line. I have an older GPU rated for 200W, and it has worked fine for years.

Swapping in the RX 480 with its 150-180W draw would cause no issues---especially after this driver fix. All power above the 75W limit for the PCIe slot will now be drawn from the ancillary power connector, as it should be. This is the same as previous cards, among them the 250-300W monstrosities marketed as Fury/Titan.