When we reviewed the new RX 480, we found a lot to like, but other sleuths managed to dig a little deeper and found problems, namely: the card was exceeding PCIe spec for power draw. That may sound bad, and it's definitely not good, but in speaking with several motherboard companies, most of them felt it was a non-issue. Regardless, AMD promised to release a driver update that would address the problem, and today AMD has released their Crimson 16.7.1 drivers that can put the kibosh on the Radeon RX 480's overzealous power draw.
There were actually two issues related to power. The first was pulling too much power from the PCIe slot and exceeding its 75W power limit, but reviewers also found that AMD's introductory Polaris part was sometimes exceeding its rated total power consumption of 150W. That was less of a concern than overdrawing through the PCIe slot connector, but a concern nonetheless. AMD potentially solves both issues with its Crimson 16.7.1 driver. We say "potentially" because it's up to end users to decide if they want to reduce the overall power consumption at the expense of performance.
The first thing the Crimson 16.7.1 driver update does is redistribute some of the power load from the PCIe slot to the Radeon RX 480's single 6-pin PCIe power connector. This doesn't reduce the total power consumption, but it does bring the power draw on the PCIe slot within spec, thereby alleviating concerns of the card damaging motherboards.
As a result of this rejiggering, the power draw in the 6-pin PCIe connector goes over spec. That shouldn't be much of an issue—it's better equipped to handle the added power draw than a motherboard's PCIe slot—but if that's still a concern, there's an optional "compatibility" toggle in Crimson's Global Settings that brings down the total power consumption of the card. Enabling compatibility mode means everything is under spec. There's a performance hit for doing so, though AMD claims it's "minimal" and offset by performance tweaks introduced by Crimson 16.7.1, which bumps performance in popular titles by up to 3 percent. Note that the toggle is turned off by default.
If you're concerned about this power business, our GPU editor, Jarred, used to do Bitcoin mining and had ASICs pulling well over 200W per 6-pin connector. With a good power supply, even that wasn't a problem, so he at least isn't worried about exceeding the 6-pin connector's 75W spec by 25-50W. And it's not like this is the first card ever to go over the 75W spec; cards from both AMD and Nvidia have done that in the past, particularly factory overclocked models. Still, AMD is taking the 'better safe than sorry' approach, or at least giving their users the opportunity to do so.
Also worth noting is that the current issue only affects the reference RX 480 cards. Custom AIB cards are more likely to offer factory overclocks and come with an 8-pin PEG connector. 8-pin PEG allows up to 150W, and combined with the 75W from the PCIe slot the RX 480 should have ample headroom, even with overclocking.
In addition to the power draw issue and performance upgrades, AMD says Crimson 16.7.1 fixes the following issues:
- Radeon RX 480 limited PCI-E Bandwidth (PCI-E bandwidth is now at the correct speed on the Radeon RX 480) with Radeon Software Crimson Edition 16.7.1.
- Minor stuttering no longer occurs in Grand Theft Auto V on Radeon RX 480 with Radeon Software Crimson Edition 16.7.1.
- Video corruption will not be observed in DOOM with resolutions above 1920x1080 with Radeon Software Crimson Edition 16.7.1.
- Hitman graphical corruption no longer occurs when the game is set to use DirectX12 API and using zoom with weapons with Radeon Software Crimson Edition 16.7.1.
- Display will not exhibit minor flicker on Radeon RX 480 when Freesync is enabled on a games launch or exit with Radeon Software Crimson Edition 16.7.1.
You can download the Crimson 16.7.1 driver update here.