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
First Thoughts
Bringing our preview of DirectX 12 to a close, what we’re seeing today is both a promising sign of what has been accomplished so far and a reminder of what is left to do. As it stands much of DirectX 12’s story remains to be told – features, feature levels, developer support, and more will only finally be unveiled by Microsoft next month at GDC 2015. So today’s preview is much more of a beginning than an end when it comes to sizing up the future of DirectX.
But for the time being we’re finally at a point where we can say the pieces are coming together, and we can finally see parts of the bigger picture. Drivers, APIs, and applications are starting to arrive, giving us our first look at DirectX 12’s performance. And we have to say we like what we’ve seen so far.
With DirectX 12 Microsoft and its partners set out to create a cross-vendor but still low-level API, and while there was admittedly little doubt they could pull it off, there has always been the question of how well they could do it. What kind of improvements and performance could you truly wring out of a new API when it has to work across different products and can never entirely avoid abstraction? The answer as it turns out is that you can still enjoy all of the major benefits of a low-level API, not the least of which are the incredible improvements in CPU efficiency and multi-threading.
That said, any time we’re looking at an early preview it’s important to keep our expectations in check, and that is especially the case with DirectX 12. Star Swarm is a best case scenario and designed to be a best case scenario; it isn’t so much a measure of real world performance as it is technological potential.
But to that end, it’s clear that DirectX 12 has a lot of potential in the right hands and the right circumstances. It isn’t going to be easy to master, and I suspect it won’t be a quick transition, but I am very interested in seeing what developers can do with this API. With the reduced overhead, the better threading, and ultimately a vastly more efficient means of submitting draw calls, there’s a lot of potential waiting to be exploited.
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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.