Friday, July 8th 2016
AMD Releases PCI-Express Power Draw Fix, We Tested, Confirmed, Works
Earlier today, AMD has posted a new Radeon Crimson Edition Beta, 16.7.1, which actually includes two fixes for the reported PCI-Express overcurrent issue that kept Internet people busy the last days.
The driver changelog mentions the following: "Radeon RX 480's power distribution has been improved for AMD reference boards, lowering the current drawn from the PCIe bus", and there's also a second item "A new "compatibility mode" UI toggle has been made available in the Global Settings menu of Radeon Settings. This option is designed to reduce total power with minimal performance impact if end users experience any further issues."
In order to adjust the power distribution between PCI-Express slot power and power drawn from the PCI-Express 6-pin power connector, AMD uses a feature of the IR3567 voltage controller that's used on all reference design cards.
This feature lets you adjust the power phase balance by changing the controller's configuration via I2C (a method to talk to the voltage controller directly, something that GPU-Z uses too, to monitor VRM temperature, for example). By default, power draw is split 50/50 between slot and 6-pin, this can be adjusted per-phase, by a value between 0 to 15. AMD has chosen a setting of 13 for phases 1, 2 and 3, which effectively shifts some power draw from the slot away onto the 6-pin connector, I'm unsure why they did not pick a setting of 15 (which I've tested to shift even more power).
The second adjustment is an option inside Radeon Settings, called "Compatibility Mode", kinda vague, and the tooltip doesn't reveal anything else either. Out of the box, the setting defaults to off and should only be employed by people who still run into trouble, even with the adjusted power distribution from the first change, which is always on and has no performance impact. When Compatibility Mode is enabled, it will slightly limit the performance of the GPU, which results in reduced overall power draw.
We tested these options, below you will find our results using Metro Last Light (with the card being warmed up before the test run). First we measured power consumption using the previous 16.6.2 driver, then we installed 16.7.1 (while keeping Compatibility Mode off), then we turned Compatibility Mode on.
As you can see, just the power-shift alone, while working, is not completely sufficient to reduce slot power below 75 W, we measured 76 W. As the name suggests, the changed power distribution results in increased power draw from 6-pin, which can easily handle slightly higher power draw though.
With the Compatibility Mode option enabled, power from the slot goes down to 71 W only, which is perfectly safe, but will cost performance.
AMD has also promised improved overall performance with 16.7.1, so we took a look at performance, using Metro again.
Here you can see that the new driver adds about 2.3% performance, which is a pretty decent improvement. Once you enable Compatibility Mode though, performance goes down slightly below the original result (0.8% lower), which means Compatibility Mode costs you around 3%, in case you really want to use it. I do not recommend using Compatibility Mode, personally I don't think anyone with a somewhat modern computer would have run into any issues due to the increased power draw in the first place, neither did AMD. It is good to see that AMD still chose to address the problem, and solved it fully, in a good way, and quick.
The driver changelog mentions the following: "Radeon RX 480's power distribution has been improved for AMD reference boards, lowering the current drawn from the PCIe bus", and there's also a second item "A new "compatibility mode" UI toggle has been made available in the Global Settings menu of Radeon Settings. This option is designed to reduce total power with minimal performance impact if end users experience any further issues."
The second adjustment is an option inside Radeon Settings, called "Compatibility Mode", kinda vague, and the tooltip doesn't reveal anything else either. Out of the box, the setting defaults to off and should only be employed by people who still run into trouble, even with the adjusted power distribution from the first change, which is always on and has no performance impact. When Compatibility Mode is enabled, it will slightly limit the performance of the GPU, which results in reduced overall power draw.
We tested these options, below you will find our results using Metro Last Light (with the card being warmed up before the test run). First we measured power consumption using the previous 16.6.2 driver, then we installed 16.7.1 (while keeping Compatibility Mode off), then we turned Compatibility Mode on.
With the Compatibility Mode option enabled, power from the slot goes down to 71 W only, which is perfectly safe, but will cost performance.
AMD has also promised improved overall performance with 16.7.1, so we took a look at performance, using Metro again.
147 Comments on AMD Releases PCI-Express Power Draw Fix, We Tested, Confirmed, Works
www.techpowerup.com/forums/threads/gtx1070-fe-pcie-gate.224024/
Oh and did I forget the dual link DVI defect of 1070/1080? Or the VR defect of 1070/1080?
Anyway, I think we all agree it's good to see AMD getting close to GM204's performance per watt, and fixing these problems which pop up with new card launches.
They gave you a driver update.. Which is totally normal and they can improve performance in "some games" while hurting it in others..
Truth is if you enable compatibility mode, you lose 3%..
The driver update is just a driver update.. All cards get them..
You lost 3% with the fix..
Ok.. Scream about the driver update now again, as if it is a valid response..lol..
That being said.. Did it ever really require a fix? I mean who's hardware could this possibly harm?
Just leave compatibility mode off I guess..In my experience around here.. people who call others fanboys are in fact themselves, fan boys..
If that's what you consider and intelligent response.
/yawn..
But seriously dude, your posts are incredibly immature and stink of bitterness. Why try so hard to focus on Fanboys? Don't you see the absolute irony in what you do?
Seriously, please try to post about the issue in the OP without trying to make it a gutter fight with the 'other' side.
Neither team makes perfect products. Neither team makes perfect drivers. People aren't perfect either and we'll get people here that always poke fun (talking to you @Fluffmeister :p). But fluff isn't hostile. Some people downright are and you're well on that path. It's unpleasant.
You don't like Nvidia, or you don't like their fanboys, neither do I. But as soon as you pick up the sword to fight them, you're in the other camp be default. Rise above it and help keep TPU more mature than other sites. Please?
www.techpowerup.com/forums/threads/ek-water-blocks-ready-with-radeon-rx-480-full-coverage-block.223784/
But here's the thing. It's obviously cheaper per mm, or AMD wouldn't be selling these cards for so cheap. That's part of the nice thing here when it comes to what AMD offers, is it shows something really interesting about what GloFo offers. But that's something that belongs in an entirely different thread. I'm kind of happy both with AMD and GloFo at this point. What that means in the long run is where the money is. :P
But here's the thing. It's obviously cheaper per mm, or AMD wouldn't be selling these cards for so cheap. That's part of the nice thing here when it comes to what AMD offers, is it shows something really interesting about what GloFo offers. But that's something that belongs in an entirely different thread. I'm kind of happy both with AMD and GloFo at this point. What that means in the long run is where the money is. :P