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.
Facebook
Twitter
RSS
113 Comments
View All Comments
silverblue - Saturday, March 28, 2015 - link
Well, varying results aside, I've heard of scores in the region of eight million. That would theoretically (if other results are anything to go off) put it around the level of a mildly-overclocked i3 (stock about 7.5m). Definitely worth bearing in mind the more-than-six-cores scaling limitation showcased by this test - AMD's own tests show this happening to the 8350, meaning that the Mantle score - which can scale to more cores - should be higher. Incidentally, the DX11 scores seem to be in the low 600,000s with a slight regression in the MT test. I saw these 8350 figures in some comments somewhere but forgot where so I do apologise for not being able to back them up, however the Intel results can be found here:http://www.pcworld.com/article/2900814/tested-dire...
I suppose it's all hearsay until a site actually does a CPU comparison involving both Intel and AMD processors. Draw calls are also just a synthetic; I can't see AMD's gaming performance leaping through the stratosphere overnight, and Intel stands to benefit a lot here as well.
silverblue - Saturday, March 28, 2015 - link
Sorry, stock i3 about 7.1m.oneb1t - Saturday, March 28, 2015 - link
my fx-8320@4.7ghz + R9 290x does 14.4mil :) in mantleLaststop311 - Friday, March 27, 2015 - link
I think AMD APU's are the biggest winner here. Since draw calls help lift cpu bottlenecks and the apu's have 4 weaker cores the lack of dx11 to be able to really utilize multi core for draw calls means the weak single threaded performance of the apus could really hold things back here. DX12 will be able to shift the bottleneck back to the igpu of the apu's for a lot of games and really help make more games playable at 1080p with higher settings or at least same settings and smoother.If only AMD would release an updated version of the 20 cu design for the ps4 using GCN 1.3 cores + 16GB of 2nd generation 3d HBM memory directly on top that the cpu or gpu could use, not only would you have a rly fast 1080p capable gaming chip you could design radically new motherboards that omit ram slots entirely. Could have new mini itx boards that have room for more sata ports and usb headers and fan headers and more room available for vrm's and cool it with good water cooling like the thermaltake 3.0 360mm rad AIO and good TIM like the coollaboratory liquid metal ultra. Or you could even take it the super compact direction and even create a smaller board than mini-itx and turn it into an ultimate htpc. And as well as the reduced size your whole system would benefit from the massive bandwidth (1.2TB/sec) and reduced latency. The memory pool could respond in real time to add more space for the gpu as necessary and since apu's are really only for 1080p that will never be a problem. I know this will probably never happen but if it did i would 100% build my htpc with an apu like that
Laststop311 - Saturday, March 28, 2015 - link
As a side question, Is there some contractual agreement that will not allow AMD to sell these large 20 cu designed APU's on the regular pc market? Does sony have exclusive rights to the chip and the techniques used to make such a large igpu? Or is it die size and cost that scares AMD from making the chip for the PC market as their would be a much higher price compared to current apu's? I'm sure 4 excavator cores cant be much bigger than 8 jaguar so if its doable with 8 jaguar it should be doable with 4 excavator, especially if they put it on the 16/14nm finfet node?silverblue - Saturday, March 28, 2015 - link
I'm sure Sony would only be bothered if AMD couldn't fulfill their orders. A PC built to offer exactly the same as the PS4 would generally cost more anyway.They can't very well go from an eight FPU design to one with two/four depending on how you look at it, even if the clocks are much higher. I think you'd need to wait for the next generation of consoles.
FriendlyUser - Saturday, March 28, 2015 - link
I really hope the developers put this to good use. I am also particularly excited about multicore scaling, since single threaded performance has stagnated (yes, even in the Intel camp).jabber - Saturday, March 28, 2015 - link
I think this shows that AMD has got a big boost from being the main partner with Microsoft on the Xbox. It's meant that AMD got a major seat at the top DX12 table from day one for a change. I hope to see some really interesting results now that it appears finally AMD hardware has been given some optimisation love other than Intel.Tigran - Saturday, March 28, 2015 - link
>>> Finally with 2 cores many of our configurations are CPU limited. The baseline changes a bit – DX11MT ceases to be effective since 1 core must be reserved for the display driver – and the fastest cards have lost quite a bit of performance here. None the less, the AMD cards can still hit 10M+ draw calls per second with just 2 cores, and the GTX 980/680 are close behind at 9.4M draw calls per second. Which is again a minimum 6.7x increase in draw call throughput versus DirectX 11, showing that even on relatively low performance CPUs the draw call gains from DirectX 12 are substantial. <<<Can you please explain how can it be? I thought the main advantage of new APIs is the workload of all CPU cores (instead of one in DX11). If so, should't the performance double in 2-core mode?Why there is 6.7x increase in draw call instead of 2x ?
Tigran - Saturday, March 28, 2015 - link
Just to make it clear: I know there such advantage of Mantle and DX12 as direct addressing GPU, w/o CPU. But this test is about draw calls, requested from CPU to GPU. How can we boost the number of draw calls apart from using additional CPU core?