AMD RX 480 PCIe Slot Power Draw Issue Detailed
PC Perspective, a well respected technology publication, has since published its results upon further investigating the issue. Ryan Shrout, Editor-In-Chief at PCPer.com, conducted PCIe slot & 6-pin power draw testing with an elaborate setup that interrupts any current going through the PCIe slot and 6-pin power connector before it goes to the card.
To mimic a realistic workload the power measurements were taken in The Witcher 3 & Rise Of The Tomb Raider. In Rise Of The Tomb Raider the load on the PCIe slot’s twelve volt power rail hovered around 70 watts throughout with a couple of spikes going up to 77 watts.
Credit : PCPer.com
In The Witcher 3 the results were nearly identical. Power draw from the motherboard’s 12 volt rail hovered around ~73 watts throughout with two, less than one second, spikes going up to 77 watts. Clearly then on both occasions the RX 480 exceeded the 75 watts. In both occasions however it was marginal at best, lasting for less than one second.
AMD Radeon RX 480 Overclocking Limitations investigated
Credit : PCPer.com
Moving over to overclocked results the story changes. Using the very same Witcher 3 benchmarking run PCPer’s overclocked RX 480 drew up to 90 watts from the PCIe slot. So clearly this turns from a non-issue to something far more serious. Although Ryan Shrout notes :
Because this occurs only with overclocked settings, AMD is not actually responsible for the specification breach in this specific instance, even though the company has talked about the overclocking headroom available on the RX 480 directly.
This is a good reminder as to why GPU vendors, both Nvidia & AMD, are emphatic about overclocking voiding the warranty. Something that users should keep in mind. It’s clear then that if you intend to overclock you’ll be much better served with a custom RX 480 from AMD’s AIB partners. Sapphire, XFX, Asus & MSI all have their own custom RX 480 designs lineup for release.
And don't forget this little tidbit from the pcper article:
For its part, AMD has acknowledged the issue publicly during its launch day AMA on Reddit and to me through email. They have stated they are looking into the issue and may even be able to come up with a software-based fix. I hope that's the case and I'll be curious if there are any performance changes that occur because of it. Consider this space reserved after a more thorough discussion with the Radeon team.
amdmatt - Any updates on the last bit?