Exploring DirectX 12: 3DMark API Overhead Feature Test
by Ryan Smith & Ian Cutress on March 27, 2015 8:00 AM EST- Posted in
- GPUs
- Radeon
- Futuremark
- GeForce
- 3DMark
- DirectX 12
Closing Thoughts
Wrapping things up, Futuremark’s latest benchmark certainly gives us a new view on DirectX 12, and of course another data point in looking at the performance of the forthcoming API.
Since being announced last year – and really, since Mantle was announced in 2013 – the initial focus on low-level APIs has been on draw call throughput, and for good reason. The current high-level API paradigm has significant CPU overhead and at the same time fails to scale well with multiple CPU cores, leading to a sort of worst-case scenario for trying to push draw calls. At the same time console developers have low enjoyed lower-level access and the accompanying improvement in draw calls, a benefit that is an issue for the PC in the age of so many multiplatform titles.
DirectX 12 then will be a radical overhaul to how GPU programming works, but at its most basic level it’s a fix for the draw call problem. And as we’ve seen in Star Swarm and now the 3DMark API Overhead Feature Test, the results are nothing short of dramatic. With the low-level API offering a 10x-20x increase in draw call throughput, any sort of draw call problems the PC was facing with high-level APIs is thoroughly put to rest by the new API. With the ability to push upwards of 20 million draw calls per second, PC developers should finally be able to break away from doing tricks to minimize draw calls in the name of performance and focus on other aspects of game design.
GDC 2014 - DirectX 12 Unveiled: 3DMark 2011 CPU Time: Direct3D 11 vs. Direct3D 12
Of course at the same time we need to be clear that 3DMark’s API Overhead Feature Test is a synthetic test – and is so by design – so the performance we’re looking at today is just one small slice of the overall performance picture. Real world game performance gains will undoubtedly be much smaller, especially if games aren’t using a large number of draw calls in the first place. But the important part is that it sets the stage for future games to use a much larger number of draw calls and/or spend less time trying to minimize the number of calls. And of course we can’t ignore the multi-threading benefits from DirectX 12, as while multi-threaded games are relatively old now, the inability to scale up throughput with additional cores has always been an issue that DirectX 12 will help to solve.
Ultimately we’re looking at just one test, and a synthetic test at that, but as gamers if we want better understand why game developers such as Johan Andersson have been pushing so hard for low-level APIs, the results of this benchmark are exactly why. From discrete to integrated, top to bottom, every performance level of PC stands to gain from DirectX 12, and for virtually all of them the draw call gains are going to be immense. DirectX 12 won’t change the world, but it will change the face of game programming for the better, and it will be very interesting to see just what developers can do with the API starting later this year.
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chizow - Friday, March 27, 2015 - link
Yeah buddy! Bring on DX12, aka Low Level API Done Right.Also fun to note all the rumors and speculation of AMD's poor DX11 MT driver support look to be real (virtually no DX11 ST to MT scaling and both lower than Nvidia DX11), but it is also obvious their efforts with Mantle have given them a nice base for their DX12 driver, at least in synthetic max draw call tests.
Main benefits for DX12 will be for CPU limited games on fast hardware, especially RTS and MMO type games where the CPU tends to be the bottleneck. It will also be interesting to see what impact it has on higher-end set-ups like high-end multi-GPU. Mantle was supposed to show us the benefits in scaling, but due to piecemeal support and the fact multi-GPU needed much more attention with Mantle, CF was often left in a broken state.
Barilla - Friday, March 27, 2015 - link
I really hope dx12 and it's increase in draw call throughput will bring us greater scene complexity, i mean more "real" objects that could be interacted with rather than tricks like textures that make us think there is depth to them while in reality it's just clever artwork. Also objects like leaves, stones, grass etc. I think this would bring much better immersion in the games than just trying to constantly up the polygon count on characters and find new ways to animate hair. Maybe I'm the odd one, but i often focus much more on the game world rather than the characters.MobiusPizza - Friday, March 27, 2015 - link
I can see how FutureMark can help make the next gen MineCraft title :Ptipoo - Friday, March 27, 2015 - link
Can Intel do any more on the driver side to see more DX12 gains, or is it all GPU front end limited at this point?mczak - Friday, March 27, 2015 - link
I suspect for the chips listed it's about as good as it will get. Note that these are all Haswell GT2 chips - GT3 doubles up on some fixed function blocks in the frontend, though I don't know if it would help (the command streamer is supposedly the same so if it's limited there it wouldn't help).The results could be better with Broadwell, though (be it GT2 or GT3).
tipoo - Friday, March 27, 2015 - link
The older article on DX12 showed GT3/3e don't see much more gain past GT2, because while many things are doubled, the front end isn't. Command input limited.I haven't heard that Broadwell is different there.
eanazag - Friday, March 27, 2015 - link
DX12 is exciting for PC laptop and tablet gaming.My desktop can heat the room when gaming and I believe that DX12 and FPS limits could allow me to play cooler next summer. I'd like to see some FPS limiting options if it can reduce heat. During the winter I don't care. I pretty much stop gaming during the summer; at least with the desktop.
martixy - Friday, March 27, 2015 - link
I like this. Very much. The industry needs a clean reset and this is a perfect opportunity...Now if only the business side was as easy to overhaul as the technical side. :)
KaarlisK - Friday, March 27, 2015 - link
I can see the 4770R (GT3e) in the system specifications, but I do not see it in any of the charts. What happened?tipoo - Friday, March 27, 2015 - link
That one I'd definitely be interested in, would the higher bandwidth it has allow any more DX12 gains?