Overclocking

Finally, no review of a high-end video card would be complete without a look at overclocking performance.

To get right to the point here, overclockers looking at out of the box overclocking performance are going to come away disappointed. While cooling and power delivery are overbuilt, in other respects the R9 Fury X is very locked down when it comes to overclocking. There is no voltage control at this time (even unofficial), there is no official HBM clockspeed control, and the card’s voltage profile has been finely tuned to avoid needing to supply the card with more voltage than is necessary. As a result the card has relatively little overclocking potential without voltage adjustments.

So what do we get for overclocking?

Radeon R9 Fury X Overclocking
  Stock Overclocked
Boost Clock 1050Mhz 1125MHz
Memory Clock 1Gbps (500MHz DDR) 1Gbps (500MHz DDR)
Max Voltage N/A N/A

Our efforts net us 75MHz, which is actually 25MHz less than what AMD published in their reviewer’s guide. Even 100MHz would lead to artifacting in some games, requiring that we step down to a 75MHz overclock to have a safe and sustainable overclock.

The end result is that the overclocked R9 Fury X runs at 1125MHz core and 1Gbps memory, a 75MHz (7%) increase in the GPU clockspeed and 0% increase in the memory clockspeed. This puts a very narrow window on expected performance gains, as we shouldn’t exceed a 7% gain in any game, and will almost certainly come in below 7% in most games.

OC: Battlefield 4 - 3840x2160 - Ultra Quality - 0x MSAA

Our gaming benchmarks find just that. A few percent performance improvement there, a 5% improvement there. Overall we wouldn’t go as far as saying there no reason to overclock, but with such limited gains it’s hardly worth the trouble right now.

True overclocking is going to have to involve BIOS modding, a riskier and warranty-voiding strategy, but one that should be far more rewarding. With more voltage I have little doubt that R9 Fury X could clock higher, though it’s impossible to guess by how much at this time. In any case the card is certainly built for it, as the oversized cooler, high power delivery capabilities, and dual BIOS switch provide all the components necessary for such an overclocking attempt.

Meanwhile HBM is a completely different bag, and while unofficial overclocking is looking promising, as a new technology it will take some time to get a good feel for it and understand just what kind of performance improvements it can deliver. The R9 Fury X is starting out with quite a bit of memory bandwidth right off the bat (512GB/sec), so it may not be bandwidth starved as often as other cards like the R9 290X was.

Power, Temperature, & Noise Final Words
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  • Navvie - Thursday, July 2, 2015 - link

    "Which is not say I’m looking" (paragraph 5, first line).

    Missing a "to" I think.
  • watzupken - Thursday, July 2, 2015 - link

    Brilliant review. Well worth the wait. Thanks Ryan.
  • Taracta - Thursday, July 2, 2015 - link

    ROPs, ROPs, ROPs! Hows can they ~ double everything else and keep the same amount of ROPs and expect to win?
  • Thatguy97 - Thursday, July 2, 2015 - link

    maybe something to do with cost or yield
  • tipoo - Thursday, July 2, 2015 - link

    They literally hit the size limits interposers can scale up to with this chip - so they can't make it any bigger to pack more transistors for more ROPs, until a die shrink. So they decided on a tradeoff, favouring other things than ROPs.
  • Kevin G - Thursday, July 2, 2015 - link

    They had a monster shader count and likely would be fine if they went to 3840 max to make room for more ROPs. 96 or 128 ROPs would have been impressive and really made this chip push lots of pixels. With HBM and the new delta color compression algorithm, there should be enough bandwidth to support these additional ROPs without bottle necking them.

    AMD also scaled the number of TMUs with the shaders but it likely wouldn't have hurt to have increased them by 50% too. Alternatively AMD could have redesigned the TMUs to have better 16 bit per channel texture support. Either of these changes would have put the texel throughput well beyond the GM200's theoretical throughput. I have a feeling that this is one of the bottlenecks that helps the GM200 pull ahead of Fiji.
  • tipoo - Friday, July 3, 2015 - link

    Not saying it was the best tradeoff - just explaining. They quite literally could not go bigger in this case.
  • testbug00 - Sunday, July 5, 2015 - link

    the performances scaling as resolution increase is better than Nvidia, implying the ROPs aren't the bottleneck...
  • chizow - Sunday, July 5, 2015 - link

    No, that implies the shaders are the bottleneck at higher resolutions while ROP/fillrate/geometry remained constant. While Nvidia's bottleneck at lower resolutions isn't shader bound but their higher ROP/fillrate allows them to realize this benefit in actual FPS, AMD's ROPs are saturated and simply can't produce more frames.
  • Ryan Smith - Thursday, July 2, 2015 - link

    Right now there's not a lot of evidence for R9 Fury X being ROP limited. The performance we're seeing does not have any tell-tale signs of being ROP-bound, only hints here and there that may be the ROPs, or could just as well be the front-end.

    While Hawaii was due for the update, I'm not so sure we need to jump up in ROPs again so soon.

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