Updated July 6: AMD has issued another statement regarding the RX 480's excessive current draw from the PCIe bus. While the company claims that the reported power draws "will not pose a risk of damage to motherboards," it is releasing a driver in the next 48 hours that changes the power distribution on the RX 480, in theory lowering current drawn from the PCIe bus.
There was some speculation that if AMD reduced the power draw of the card, the clock speed of the RX 480 would have be reduced too, and in turn this would reduce performance. While AMD hasn't quite admitted that's the case, it is implementing a separate "compatibility" toggle switch inside the Radeon driver, which reduces the total power draw of the RX 480.
AMD says this toggle will have "minimal performance impact," but at the same time has bumped up performance in key titles with some driver tweaks by as much as three percent. This "should substantially offset the performance impact for users who choose to activate the compatibility toggle," it claims. You can read the full statement from AMD below.
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.
AMD is committed to delivering high quality and high performance products, and we’ll continue to provide users with more control over their product’s performance and efficiency. We appreciate all the feedback so far, and we’ll continue to bring further performance and performance/W optimizations to the Radeon RX 480.
Original story
Last week, AMD released its budget-minded RX 480 graphics card to largely critical acclaim. Unfortunately, the positive reception has been overshadowed by reports that the RX 480 exceeds its 150W target TDP. Furthermore, that extra power draw seems to be coming from the PCIe bus, with the card pulling as much as 90W from its PCIe slot, far exceeding the specified 75W maximum and potentially causing stability issues with certain motherboards.
The tests, conducted by Tom's Hardware, caused quite the stir over on Reddit. Some Reddit users even conducted their own tests on retail versions of the RX 480, with some (though not all) throwing up similar results. AMD has now issued a statement, admitting that the tuning on certain RX 480 cards is "not optimal."
As you know, we continuously tune our GPUs in order to maximise their performance within their given power envelopes and the speed of the memory interface, which in this case is an unprecedented 8Gbps for GDDR5. Recently, we identified select scenarios where the tuning of some RX 480 boards was not optimal. Fortunately, we can adjust the GPU's tuning via software in order to resolve this issue. We are already testing a driver that implements a fix, and we will provide an update to the community on our progress on Tuesday.
While AMD's statement doesn't indicate precisely what's causing the issues with the RX 480, if it is exceeding its 150W target, either something is causing the card to run in the wrong power state, or it's exceeding its power limit and needs to be throttled back. There's some speculation that AMD was simply too ambitious with the RX 480's power draw, and that the addition of an 8-pin power connector would solve the issue, as well as open up far more headroom for overclocking.
With only reference designs on sale that use a single 6-pin power connector, unfortunately it'll be a little while until that theory can be put to the test.
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