The DirectX 12 Performance Preview: AMD, NVIDIA, & Star Swarm
by Ryan Smith on February 6, 2015 2:00 PM EST- Posted in
- GPUs
- AMD
- Microsoft
- NVIDIA
- DirectX 12
About a year and a half ago AMD kicked off the public half of a race to improve the state of graphics APIs. Dubbed "Mantle", AMD’s in-house API for their Radeon cards stripped away the abstraction and inefficiencies of traditional high-level APIs like DirectX 11 and OpenGL 4, and instead gave developers a means to access the GPU in a low-level, game console-like manner. The impetus: with a low-level API, engine developers could achieve better performance than with a high-level API, sometimes vastly exceeding what DirectX and OpenGL could offer.
While AMD was the first such company to publicly announce their low-level API, they were not the last. 2014 saw the announcement of APIs such as DirectX 12, OpenGL Next, and Apple’s Metal, all of which would implement similar ideas for similar performance reasons. It was a renaissance in the graphics API space after many years of slow progress, and one desperately needed to keep pace with the progress of both GPUs and CPUs.
In the PC graphics space we’ve already seen how early versions of Mantle perform, with Mantle offering some substantial boosts in performance, especially in CPU-bound scenarios. As awesome as Mantle is though, it is currently a de-facto proprietary AMD API, which means it can only be used with AMD GPUs; what about NVIDIA and Intel GPUs? For that we turn towards DirectX, Microsoft’s traditional cross-vendor API that will be making the same jump as Mantle, but using a common API for the benefit of every vendor in the Windows ecosystem.
DirectX 12 was first announced at GDC 2014, where Microsoft unveiled the existence of the new API along with their planned goals, a brief demonstration of very early code, and limited technical details about how the API would work. Since then Microsoft has been hard at work on DirectX 12 as part of the larger Windows 10 development effort, culminating in the release of the latest Windows 10 Technical Preview, Build 9926, which is shipping with an early preview version of DirectX 12.
GDC 2014 - DirectX 12 Unveiled: 3DMark 2011 CPU Time: Direct3D 11 vs. Direct3D 12
With the various pieces of Microsoft’s latest API finally coming together, today we will be taking our first look at the performance future of DirectX. The API is stabilizing, video card drivers are improving, and the first DirectX 12 application has been written; Microsoft and their partners are finally ready to show off DirectX 12. To that end, today we’ll looking at DirectX 12 through Oxide Games’ Star Swarm benchmark, our first DirectX 12 application and a true API efficiency torture test.
Does DirectX 12 bring the same kind of performance benefits we saw with Mantle? Can it resolve the CPU bottlenecking that DirectX 11 struggles with? How well does the concept of a low-level API work for a common API with disparate hardware? Let’s find out!
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ObscureAngel - Saturday, February 7, 2015 - link
Ryan can you do an article demonstrating the low performance of AMD GPUs in low end CPUs like i3 or anything, in more CPU Bound games comparing to nvidia GPUs in the same CPUs?Unworthy websites have done it, like GameGPU.ru or Digital foundry.
They don't have so much expression because well, sometimes they are a bit dumb.
I confirmed that recently with my own benchmarks, AMD GPUs really have much less performance in the same CPU (low-end CPUs) than an nvidia GPU.
If you look into it and publish maybe that would put a little pressure on AMD and they start to look into it.
But not sure if you can do it, AMD gives your website AMD GPUS and CPUs to benchmark, i'm pretty sure AMD wouldn't like to read the truth..
But since Futuremark new 3dmark is close to release that new benchmark that benchmarks overhead/drawcalls.
It could be nice to give a little highlight of that problem with AMD.
Many people are starting to notice that problem, but AMD are ignoring everyone that claims the lack of performance, so we need somebody strong like Anandtech or other website to analyse these problems and publish to everyone see that something is wrong.
Keep in mind that AMD just fixed the frametime problem in crossfire, cause one website (which i dont remember) publish that, and people start to complain about it, and they start to fix it, and they really fix it.
Now, we already have the complains but we dont have the upper voice like you guys.
okp247 - Sunday, February 8, 2015 - link
Sorry, my bad. The numbers I've stated in the above posts were indeed from either the Follow or Attract scenario.So what is up with the underutilized AMD cards? Clearly, they are not stretching their legs under DX11. In the article you touch upon the CPU batch submission times, and how these are taking a (relatively) long time on the AMD cards. Is this the case also with other draw-call heavy games or is it a fluke in Star Swarm?
ObscureAngel - Monday, February 9, 2015 - link
It happens on games too.I did a video and everything about it.
Spread the word, we need to get AMD attention for this..Since they dont answer me i decided to publicly start to say bad things about them :D
https://www.youtube.com/watch?v=2-nvGOK6ud8
killeak - Saturday, February 7, 2015 - link
Both API (D3D12 and Mantle) are under NDA. In the case of D3D12, in theory if you are working with D3D12 you can't speak about it unless you have explicit authorization from MS. The same with Mantle and AMD.I hope D3D12 goes public by GDC time, I mean the public beta no the final version, after that things will change ;)
Klimax - Saturday, February 7, 2015 - link
Thanks for numbers. They show perfectly how broken and craptastick entire POS is. There are extreme number of idiocies and stupidities in it that it couldn't pass any review by any competent developer.1)Insane number of batches. You want to have at least 100 objects in one to actually see benefit. (Civilization V default settings) To see quite better performance I would say at least 1000 objects to be in one. (Civilization V test with adjusted config) Star Swarm has between 10 to 50 times more batches then Civilization. (Precise number cannot be said as I don't have number of objects to be drawn reported from that "benchmark")
2)Absolutely insane number of superfluous calls. Things like IASetPrimitiveTopology are called (almost) each time an object is to be drawn with same parameters(constants) and with large number of batches those functions add to overhead. That's why you see such large time for DX11 draw - it has to reprocess many things repeatedly. (Some caching and shortcuts can be done as I am sure NVidia implemented them, but there are limits even for otherwise very cheap functions)
3)Simulation itself is so atrociously written that it doesn't really scale at all! This is in space, where number of intersection is very small, so you can process it at maximum possible parallelization.
360s run had 4 cores used for 5,65s with 5+ for 6,1s in total. Bad is weak word...
And I am pretty sure I haven't uncovered all. Note: I used Intel VTune for analysis 1 year ago. Since then no update came so I don't think anything changed at all... (Seeing those numbers I am sure of it)
nulian - Saturday, February 7, 2015 - link
The draw calls are misused on purpose in this demo to show how much better it has become. The advantage for normal games is they can do more light and more effects that use a lot of draw calls without breaking the performance on pc. It is one of the biggest performance different between console and PC draw calls.BehindEnemyLines - Saturday, February 7, 2015 - link
Or maybe they are doing that on purpose to show the bottleneck of DX11 API? Just a thought. If this is a "poorly" written performance demo, then you can only imagine the DX12 improvements after it's "properly" written.Teknobug - Saturday, February 7, 2015 - link
Wasn't there some kind of leaked info that DX12 was basically a copy of Mantle with DX API? Wouldn't surprise me that it'd come close to Mantle's performance.dragonsqrrl - Sunday, February 8, 2015 - link
Right, cause Microsoft only started working on DX12 when Mantle was announced...bloodypulp - Sunday, February 8, 2015 - link
You're missing the point. Mantle/D12 are so similar you could essentially call DX12 the Windows-only version of Mantle. By releasing Mantle, AMD gave developers an opportunity to utilize the new low-level APIs nearly two years before Microsoft was ready to release their own as naturally it was tied to their OS. Those developers who had the foresight to take advantage of Mantle during those two years clearly benefited. They'll launch DX12-ready games before their competitors.