AMD’s new RX480 card has launched today, which means benchmarks and power efficiency tests galore popping up across the internet. Among the many articles, reviewers at Tom’s Hardware reported something troubling regarding power draw on the PCI Express slot.
In their testing, they found that the RX480 they had received for review drew 86W through the PCIE slot. That’s 11W above the maximum 75W specification required to meet compliance.
AMD’s Senior VP and Chief Architect Raja Koduri was fortuitously present for an ‘Ask Me Anything’ event earlier today, and addressed the issue when asked (‘gfxchiptweeter’ is Koduri).
“We have extensive testing internally on our PCIE compliance and RX480 passed our testing,” he writes. “However we have received feedback from some of the reviewers on high current observed on PCIE in some cases. We are looking into these scenarios as we speak and reproduce these scenarios internally. Our engineering team is fully engaged.”
If widespread, the non-compliant power draw would be a serious issue for AMD. However, there are other possibilities. The card received for review at Tom’s could be faulty in some way, or something went array with the testing. Reviewers were working with cards that could flash the BIOS to use either 4GB or 8GB of VRAM (to save sending a pair of cards to everyone, presumably), so that’s another difference between review and market models.
For now, it’s something for AMD’s engineers to take a good look at.
Update: A further comment from AMD states that the RX480 met ‘Peripheral Component Interconnect Special Interest Group’ (PCI-SIG) compliance testing. So it passed external industry testing as well as internal tests.
“Obviously there are a few GPUs exhibiting anomalous behavior, and we’ve been in touch with these reviewers for a few days to better understand their test configurations to see how this could be possible,” that post says. “We will have more on this topic soon as we investigate, but it’s worth reminding people that only a very small number of hundreds of RX 480 reviews worldwide encountered this issue.”
Update 2 July: AMD have released a further, more public, statement in which they assert that in “select scenarios … some RX480 boards” have a power draw problem. They suggest a software-based (driver) fix will be possible, but more details will be released on 5 July. It’s turning into a messy launch for this flagship Polaris card.