Ashes of the Singularity Revisited: A Beta Look at DirectX 12 & Asynchronous Shading
by Daniel Williams & Ryan Smith on February 24, 2016 1:00 PM ESTDirectX 12 vs. DirectX 11
Now that we’ve had the chance to look at DirecX 12 performance, let’s take a look at things with DirectX 11 thrown into the mix. As a reminder, while the two rendering paths are graphically identical, the DirectX 12 path introduces the latter’s multi-core scalability along with asynchronous shading functionality. The game and the underlying Nitrous engine is designed to take advantage of both, but particularly the multi-core functionality as the game pushes some very high batch counts.
Given that we had never benchmarked Ashes under DirectX 11 before, what we had been expecting was a significant performance regression when switching to it. Instead what we found was far more surprising.
On the RTG side of matters, there is a large performance gap between DX11 and DX12 at all resolutions, increasing with the overall performance of the video card being tested. Even on the R9 290X and the 7970, using DX12 is a no brainer, as it improves performance by 20% or more.
The big surprise however is with the NVIDIA cards. For the more powerful GTX 980 Ti and GTX 780 Ti, NVIDIA doesn’t gain anything from the DX12 rendering path; in fact they lose a percent or two in performance. This means that they have very good performance under DX11 (particular the GTX 980 Ti), but it’s not doing them any favors under DX12, where as we’ve seen RTG has a rather consistent performance lead. In the past NVIDIA has gone through some pretty extreme lengths to optimize the CPU usage of their DX11 driver, so this may be the payoff from general optimizations, or even a round of Ashes-specific optimizations.
Breaking down the gains on a percentage basis at 1080p, the most CPU-demanding resolution, we find that the Fury X picks up a full 50% from DX12, followed by 29% and 23% for the R9 290X and 7970 respectively. Meanwhile at the opposite end of the spectrum are the GTX 980 Ti and GTX 780 Ti, who lose 1% and 3% respectively.
Finally, right in the middle of all of this is the GTX 680. Given what happens to the architecturally similar GTX 780 Ti, this may be a case of GPU memory limitations (this is the only 2GB NVIDIA card in this set), as there’s otherwise no reason to expect the weakest NVIDIA GPU to benefit the most from DX12.
Overall then this neatly illustrates why RTG in particular has been so gung-ho about DX12, as Ashes’ DX12 path has netted them a very significant increase in performance. To some degree however what this means is a glass half full/half empty full situation; RTG gains so much from DX12 in large part because of their poorer DX11 performance (especially on the faster cards), but on the other hand a “simple” API change has unlocked a great deal of GPU power that wasn’t otherwise being used and vaulted them well into the lead. As for NVIDIA, is it that their cards don’t benefit from DX12, or is it that their DX11 driver stack is that good to begin with? At the end of the day Ashes is just a single game – and a beta game at that – but it will be interesting to see if this is a one-off situation or if it becomes recurring.
Facebook
Twitter
RSS
153 Comments
View All Comments
extide - Wednesday, February 24, 2016 - link
If you are CPU limited, and it's using lots of threads, then yeah more cores would be faster. They were CPU limited on an overclocked 4960X, which is no slouch, that was very surprising!rhysiam - Wednesday, February 24, 2016 - link
I agree that will be very interesting. I'm surprised more hasn't been made of the seemingly pretty hard CPU limit to ~70fps, irrespective of the detail settings or resolution. And that on a still very capable 4960X @ 4.2Ghz. If we estimate Skylake has a 20% IPC advantage, that would still see the current top tier 6700K (at stock) maxing out in the mid 80s, a long way short of what you might like on a 144hz monitor. Does that mean a brand new quad core CPU like the i5 6400 with its low base clock might struggle to sustain 60fps, even on lower detail settings?I realise this is beta and all preliminary, but it's interesting nonetheless.
DanNeely - Wednesday, February 24, 2016 - link
Does DX12 Multi-adapter offer any benefits with cards that are mismatched in performance? I'm currently running a GTX 980 in my main PC and also have an older GTX 770 sitting around; would pairing them offer any speedup over just the 980, or would the faster card end up held back by the slower one?I'd be equally interested in seeing how AMD does with significantly mismatched GPUs; since they've been trying (with varying degrees of success) to push XFire between their IGPs and the significantly faster chips in midrange Radeon cards.
BigLan - Wednesday, February 24, 2016 - link
The article has a quote from the developer about using mismatched cards..."For example, you will never get more than twice the speed of the slowest video card. You would be better off just using the new card alone."
You might get some benefit, but likely not that much.
Friendly0Fire - Wednesday, February 24, 2016 - link
I think that's rather narrow minded and way too absolute. Mismatched cards can be used to their full potential, but you'd need some smart coding to make it so. For instance, you could offload some of the work to the weaker GPU, keeping the stronger one for the main rendering.One excellent example which would fully utilize two mismatched cards is VR: multiadapter rendering would be used to offload the VR projection and transformation steps to the integrated GPU in most modern CPUs, while the main GPU would do the regular rendering. The data transfer requirement is minimal, but there's a fair amount of computations required, making it an ideal scenario.
Other examples include doing post-processing on the weaker card (SSAO, subsurface scattering, screenspace reflections, etc.). The big problem is judging just how much work should be offloaded to the secondary GPU - just detecting the hardware would be extremely laborious.
Ryan Smith - Wednesday, February 24, 2016 - link
It's a correct description for how Ashes works. They implement a (relatively) straightforward AFR setup, so the cards need to be similar in performance.Senti - Wednesday, February 24, 2016 - link
What Multi-adapter does is left completely to developer. In some cases it can give you nothing, in others every bit of hardware can be useful including iGPU.extide - Wednesday, February 24, 2016 - link
Their current implementation is AFR, so the performance of the cards should be as close to identical as possible. In the future I think they may plan on offloading some of the raw compute onto a second GPU, and in that case an older slower GPU would be beneficial.Drumsticks - Wednesday, February 24, 2016 - link
These are always interesting results to see. I'm pretty excited for Polaris - I can't wait to pickup a higher end GPU to replace my old, old 7850.mattevansc3 - Wednesday, February 24, 2016 - link
Isn't Oxide's statement that they don't optimise for certain hardware a bit disingenuous?If you read their developer diaries not only was AoS built around Mantle, not only was the engine built upon Mantle but they've stated that they developed more of Mantle than AMD did.
Before DX12 was even announced Oxide were working directly with AMD and building AoS to champion Mantle and take advantage of it a low level while only supporting nVidia hardware on DX11. That of course will automatically bias results in favour of RTG even if there is no intention to do so at this stage.