Ashes GPU Performance: Single & Mixed High-End GPUs

Since seeing is believing, we’ll start things off with a look at some direct captured recordings of Ashes running the built-in benchmark. These recordings showcase a Radeon R9 Fury X and a GeForce GTX 980 Ti in AFR mode, with each video swapping the primary and secondary video card. Both videos are captures with our 2560x1440 settings and with v-sync on, though YouTube limits 60fps videos to 1080p at this time.

Overall you’d be hard-pressed to find a difference between the two videos. No matter which GPU is primary, both setups render correctly and without issue, showcasing that DirectX 12 explicit multi-adapter and Ashes’ AFR implementation on top of it is working as expected.

Diving into our results then, let’s start with performance at 2560x1440.

Ashes of the Singularity (Alpha) - 2560x1440 - High Quality - 2x MSAA

It’s interesting to note that when picking these settings, the settings were chosen first and the cards second. So the fact that the GTX 980 Ti and R9 Fury X end up being so close in average performance comes as a pleasant surprise. With AFR performance gains dependent in part on how similar the two cards are, this should give us a better look at performance than cards that differ widely in performance.

In any case what we find is that with a single card setup the GTX 980 Ti and R9 Fury X are within 5% of each other with the older driver sets we needed to use for AFR compatibility. Both AMD and NVIDIA do see some performance gains with newer driver sets, with NVIDIA picking up 8% while AMD picks up 5%.

But more importantly let’s talk about mutli-GPU setups. If everything is working correctly and there are no unexpected bottlenecks, then on paper in mixed GPU setups we should get similar results no matter which card is the primary. And indeed that’s exactly what we find here, with only 1.4fps (2%) separating the GeForce + Radeon setups. Using the Radeon Fury X as the primary card gets the best results at 70.8fps, while swapping the order to let the GTX 980 Ti lead gives us 69.4fps.

However would you believe that the mixed GPU setups are faster than the homogenous setups? Trailing the mixed setups is the R9 Fury X + R9 Fury setup, averaging 67.1fps and trailing the slower mixed setup by 3.5%. Slower still – and unexpectedly so – is the GTX 980 Ti + GTX Titan X setup, which averages just 61.6fps, some 12% slower than the GTX 980 Ti + Fury X setup. The card setup is admittedly somewhat unusual here – in order to consistently use the GTX 980 Ti as the primary card we had to make the secondary card a GTX Titan X, seeing as how we don’t have another GTX 980 Ti or a third-tier GM200 card comparable to the R9 Fury – but even so the only impact here should be that the GTX Titan X doesn’t get to stretch its legs quite as much since it needs to wait on the slightly slower GTX 980 Ti primary in order to stay in sync.

Ashes of the Singularity (Alpha) - 2560x1440 - Multi-GPU Perf. Gains

Looking at performance from the perspective of overall performance gains, the extra performance we see here isn’t going to be chart-topping – an optimized SLI/CF setup can get better than 80% gains – but overall the data here confirms our earlier raw results: we’re actually seeing a significant uptick in performance with the mixed GPU setups. R9 Fury X + GTX 980 Ti is some 75% faster than a single R9 Fury X while GTX 980 Ti + R9 Fury X is 64% faster than a single GTX 980 Ti. Meanwhile the dual AMD setup sees a 66% performance gain, followed by the dual NVIDIA setup at only 46%.

The most surprising thing about all of this is that the greatest gains are with the mixed GPU setups. It’s not immediately clear why this is – if there’s something more efficient about having each vendor and their drivers operating one GPU instead of two – or if AMD and NVIDIA are just more compatible than either company cares to admit. Either way this shows that even with Ashes’ basic AFR implementation, multi-adapter rendering is working and working well. Meanwhile the one outlier, as we briefly discussed before, is the dual NVIDIA setup, which just doesn’t scale quite as well.

Finally let’s take a quick look at the GPU utilization statistics from MSI Afterburner, with our top-performing R9 Fury X + GTX 980 Ti setup. Here we can see the R9 Fury X in its primary card role operate at near-100% load the entire time, while the GTX 980 Ti secondary card is averaging close to 90% utilization. The difference, as best as we can tell, is the fact that the secondary card has to wait on additional synchronization information from the primary card, while the primary card is always either rendering or reading in a frame from the secondary card.

3840x2160

Now we’ll kick things up a notch by increasing the resolution to 3840x2160.

Ashes of the Singularity (Alpha) - 3840x2160 - High Quality - 2x MSAA

Despite the fact that this was just a resolution increase, the performance landscape has shifted by more than we would expect here. The top configuration is still the mixed GPU configuration, with the R9 Fury X + GTX 980 Ti setup taking the top spot. However the inverse configuration of the GTX 980 Ti + R9 Fury X isn’t neck-and-neck this time, rather it’s some 15% slower. Meanwhile the pokey-at-2560 dual NVIDIA setup is now in second place by a hair, trailing the mixed GPU setup by 10%. Following that at just 0.1fps lower is the dual AMD setup with 46.7fps.

These tests are run multiple times and we can consistently get these results, so we are not looking at a fluke. At 3840x2160 the fastest setup by a respectable 10.5% margin is the R9 Fury X + GTX 980 Ti setup, which for an experimental implementation of DX12 unlinked explicit multi-adapter is quite astonishing. “Why not both” may be more than just a meme here…

From a technical perspective the fact that there’s now a wider divergence between the mixed GPU setups is unexpected, but not necessarily irrational. If the R9 Fury X is better at reading shared resources than the GTX 980 Ti – be it due to hardware differences, driver differences, or both – then that would explain what we’re seeing. Though at the same time we can’t rule out the fact that this is an early tech demo of this functionality.

Ashes of the Singularity (Alpha) - 3840x2160 - Multi-GPU Perf. Gains

As you’d expect from those raw numbers, the best perf gains are with the R9 Fury X + GTX 980 Ti, which picks up 66% over the single-GPU setups. After that the dual AMD GPU setup picks up 50%, the dual NVIDA setup a more respectable 46%, and finally the mixed GTX 980 Ti + R9 Fury X setup tops out with a 40% performance gain.

Finally, taking a quick look of GPU frametimes as reported by Ashes internal performance counters, we can see that across all of the mutli-GPU setups there’s a bit of a consistent variance going on. Overall there’s at least a few milliseconds difference between the alternating frames, with the dual NVIDIA setup faring the best while the dual AMD setup fares the worst. Otherwise the performance leader, the R9 Fury X + GTX 980 Ti, only averages a bit more variance than the dual NVIDIA setup. At least in this one instance, there’s some evidence to suggest that NVIDIA secondary cards have a harder time supplying frame data to the primary card (regardless of its make), while NVIDIA and AMD primary cards are similar in read performance.

Ashes of the Singularity: Unlinked Explicit Multi-Adapter w/AFR & The Test Ashes GPU Performance: Single & Mixed 2012 GPUs
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  • medi03 - Monday, October 26, 2015 - link

    Uhm, and what about 7970 simply being the faster card? Reply
  • Gigaplex - Monday, October 26, 2015 - link

    That would explain why 7970+680 is faster than 680+7970, but not why 680 is faster than 680+7970. Reply
  • prtskg - Wednesday, October 28, 2015 - link

    when 680 is in lead, not only it has to render frames but also assign work to 7970 and receive completed frames from it. For it to be slower than only 680 means assigning and receiving work is very slow on it. Reply
  • Hulk - Monday, October 26, 2015 - link

    Could it be that the AMD/nVidia mixed setup performs better because each card has different strengths and weaknesses and they compliment each other rather than having two cards with the same strengths and weaknesses and therefore more probable bottlenecks?
    Just a thought.
    Reply
  • DragonJujo - Monday, October 26, 2015 - link

    They didn't include any direct comparisons to matched CrossFireX or SLI so it would be a bit premature. The idea itself is quite interesting in light of the GameWorks problems that show up in AMD because of the heavy tessellation (which can be limited). Reply
  • Ryan Smith - Monday, October 26, 2015 - link

    As Ashes uses AFR, each card essentially has to stand on its own. Right now they only work together in as much as each gets assigned work, and then the secondary card ships off completed frames to the primary card for display queuing. There's no greater sharing of work; no opportunity for each card to work on what it does best. Reply
  • bug77 - Monday, October 26, 2015 - link

    Technically, this is a major achievement. But in a world where multi-GPU setups are still in the single digits, these setups will be a niche of a niche. Reply
  • Manch - Monday, October 26, 2015 - link

    I think you'll see more setups with mixed cards. If I don't have to toss my old card and simply by a new gen card with similar performance vs outlaying cash for SLI or cross fire off the bat that would be awesome. want to know if this can handle 4X x mixed cards Reply
  • fingerbob69 - Wednesday, October 28, 2015 - link

    I think this DX12 will lead to dual card set-ups becoming common if not the norm.

    I have a r9-280. In the next year or so I upgrade to either the next gen AMD OR nvidia with the 280 becoming the secondary to te new card's lead.
    Reply
  • plopke - Monday, October 26, 2015 - link

    why 3 shades of grey on some graphs(no pun intended) , maby i din't understand it , maby it is my screen but i can hardly make a distinction between the shades. Reply

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