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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inighthawki - Monday, February 9, 2015 - link
>> btw funny how "M$ would need to do huge kernel rework to bring DX12 to Win7/8" while mantle, which does similar thing, is easily capable to be "OS version independent" (sure it is amd specific but still)How do you know that DX12 will not support a number of features that Mantle will not? For example, DX12 is expected to provide the application with manual memory management, a feature not available in Mantle while running on WDDM 1.3 or below.
lordken - Tuesday, February 10, 2015 - link
what I meant is in performance terms. While mantle is able to deliver +/-same performance boost as DX12 but still on old windows kernel.Not saying DX12 wont support something that mantle wont be able to do on old windows kernel. I merely tried to highlight that same performance boost can be achieved on current OS without the need of M$ taunting gamers with Win10 (forced) upgrade for DX12
killeak - Tuesday, February 10, 2015 - link
"btw funny how "M$ would need to do huge kernel rework to bring DX12 to Win7/8" while mantle, which does similar thing, is easily capable to be "OS version independent" (sure it is amd specific but still)"Direct3D has a very different design. While APIs like OpenGL or Mantle are implemented in the drivers, Direct3D is implemented (the runtime) in the OS. That means, that no matter what hardware you have, the code that is executed under the API, is for most part, always the same. Sure, the Driver needs to expose and abstract the hardware (following another API, in this case WDDM 2.0), but the actual implementation is much more slim. Which means is much more solid and reliable.
Now, OpenGL is implemented in the driver, the OS only expose the basic C functions to create the context and the like. A good driver can make OpenGL works as fast, or even more, than D3D, but the reality says that 90% of the time, OpenGL works worse. Not just because of performance, but because each driver for each OS and each GPU has a different implementation, things usually doesn't work as you expected.
After years of working with OpenGL and D3D, the thing that I miss more of D3D when I am coding for OpenGL platforms, is the single runtime. Program once, run everywhere (well on every windows) works on D3D but not on OpenGL, hell is even harder on mobile with OpenGL ES, and the broken drivers of Mali, Qualcomm, etc. Sure, if your app is simple OpenGL works, but for AAA it just doesn't cut...
The true is, IHVs are here to sell hardware, not software, so they invest the minimum time and money on it (most of the time they optimize drivers for big AAA titles and benchmarks). For mobile, where SoCs are replaced every year, is even workse, since drivers never get mature enough. Heck, Mali for example doesn't have devices with the 700 series on the market and they already announced the 800 series, while their OpenGL ES drivers for the 600 are really bad.
Going back to Mantle and Win7/8. In the drivers, you can do what ever you want, so yes, you can make your own API and make it work wherever you want, that is why Mantle can do things low level without WDDM 2.0, it doesn't need to be common or compatible to other drivers/vendors.
Bill McGann - Tuesday, February 10, 2015 - link
Yeah, this is a huge reason why GL is largely ignored by Windows devs. D3D is extremely stable thanks to it largely being implemented by MS, and them having the power to test/certify the vendor's back-ends.GL on the other hand is the wild west, with every vendor doing whatever they like... You even have them stealing MS's terrible 90's browser-war strategies of deliberately supporting broken behavior, hoping devs will use it, so that games will break on other vendor's (strictly compliant) drivers. Any situation where vendors are abusing devs like this is pretty f'ed up.
tobi1449 - Thursday, February 12, 2015 - link
The console & pc aspect isn't going anywhere and was never meant to. AMD formulated their early press releases in a way that some people jumped the hype train before it was even built, but AMD was shut down by Microsoft and Sony pretty quickly about that.Bill McGann - Tuesday, February 10, 2015 - link
FYI mantle is very carefully specified as a vendor-agnostic API, like GL, with extensions for vendor-specific behavior.If AMD even bother launching Mantle after D3D12/GLNext appear, and if it remains AMD-only, it's because nVidia/Intel have chosen not to adopt the spec, not because AMD have deliberately made it AMD-only.
tobi1449 - Thursday, February 12, 2015 - link
a) I can see why there's resistance against adopting a competitors API.b) AFAIK AMD hasn't released anything needed to implement Mantle for other hardware yet. Sure, they've often talked about it and most of the time Mantle is mentioned this pops up, but in reality (if this is still correct) it is as locked down as say G-Sync or PhysX.
Arbie - Tuesday, February 10, 2015 - link
I closely followed graphics board technology and performance for many years. But after a certain point I realized that there are actually very few - count 'em on one hand - games that I even enjoy playing. Three of those start with "Crysis" (and the other two with "Peggle"). The Battlefield series might have the same replay interest; don't know.So unless and until there are really startling ~3x gains for the same $$, my interest in desktop graphics card performance is much more constrained by game quality than by technology. I don't want to run "Borderlands" 50% faster because... I don't want to run it at all. Or any other of the lousy console ports out there.
computertech82 - Wednesday, February 11, 2015 - link
SLIGHT PROBLEM. I think it's safe to say the dx11 vs dx12 was ran on the SAME OS 10. That probably just means dx11 runs crappy on win10, not that dx12 is so much better. I bet it would be different with win7/8 dx11 vs win10 dx12 (meaning very little difference).Notmyusualid - Thursday, February 12, 2015 - link
Good point - hadn't considered it until you mentioned it.Then the comparison should really have been dx11 - Win 7/8, dx12 - Win 10, Mantle - both (if poss).