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
Other Notes
Before jumping into our results, let’s quickly talk about testing.
For our test we are using the latest version of the Windows 10 technical preview – build 10041 – and the latest drivers from AMD, Intel, and NVIDIA. In fact for testing DirectX 12 these latest packages are the minimum versions that the test supports. Meanwhile 3DMark does of course also run on Windows Vista and later, however on Windows Vista/7/8 only the DirectX 11 and Mantle tests are available since those are the only APIs available.
From a test reliability standpoint the API Overhead Feature Test (or as we’ll call it from now, AOFT) is generally reliable under DirectX 12 and Mantle, however we would like to note that we have found it to be somewhat unreliable under DirectX 11. DirectX 11 scores have varied widely at times, and we’ve seen one configuration flip between 1.4 million draw calls per second and 1.9 million draw calls per second based on indeterminable factors.
Our best guess right now is that the variability comes from the much greater overhead of DirectX 11, and consequently all of the work that the API, video drivers, and OS are all undertaking in the background. Consequently the DirectX 11 results are good enough for what the AOFT has set out to do – showcase just how much incredibly faster DX12 and Mantle are – but it has a much higher degree of variability than our standard tests and should be treated accordingly.
Meanwhile Futuremark for their part is looking to make it clear that this is first and foremost a test to showcase API differences, and is not a hardware test designed to showcase how different components perform.
The purpose of the test is to compare API performance on a single system. It should not be used to compare component performance across different systems. Specifically, this test should not be used to compare graphics cards, since the benefit of reducing API overhead is greatest in situations where the CPU is the limiting factor.
We have of course gone and benchmarked a number of configurations to showcase how they benefit from DirectX 12 and/or Mantle, however as per Futuremark’s guidelines we are not looking to directly compare video cards. Especially since we’re often hitting the throughput limits of the command processor, something a real-world task would not suffer from.
The Test
Moving on, we also want to quickly point out the clearly beta state of the current WDDM 2.0 drivers. Of note, the DX11 results with NVIDIA’s 349.90 driver are notably lower than the results with their WDDM 1.3 driver, showing much greater variability. Meanwhile AMD’s drivers have stability issues, with our dGPU testbed locking up a couple of different times. So these drivers are clearly not at production status.
DirectX 12 Support Status | ||||
Current Status | Supported At Launch | |||
AMD GCN 1.2 (285) | Working | Yes | ||
AMD GCN 1.1 (290/260 Series) | Working | Yes | ||
AMD GCN 1.0 (7000/200 Series) | Working | Yes | ||
NVIDIA Maxwell 2 (900 Series) | Working | Yes | ||
NVIDIA Maxwell 1 (750 Series) | Working | Yes | ||
NVIDIA Kepler (600/700 Series) | Working | Yes | ||
NVIDIA Fermi (400/500 Series) | Not Active | Yes | ||
Intel Gen 7.5 (Haswell) | Working | Yes | ||
Intel Gen 8 (Broadwell) | Working | Yes |
And on that note, it should be noted that the OS and drivers are all still in development. So performance results are subject to change as Windows 10 and the WDDM 2.0 drivers get closer to finalization.
One bit of good news is that DirectX 12 support on AMD GCN 1.0 cards is up and running here, as opposed to the issues we ran into last month with Star Swarm. So other than NVIDIA’s Fermi cards, which aren’t turned on in beta drivers, we have the ability to test all of the major x86-paired GPU architectures that support DirectX 12.
For our actual testing, we’ve broken down our testing for dGPUs and for iGPUs. Given the vast performance difference between the two and the fact that the CPU and GPU are bound together in the latter, this helps to better control for relative performance.
On the dGPU side we are largely reusing our Star Swarm test configuration, meaning we’re testing the full range of working DX12-capable GPU architectures across a range of CPU configurations.
DirectX 12 Preview dGPU Testing CPU Configurations (i7-4960X) | |||
Configuration | Emulating | ||
6C/12T @ 4.2GHz | Overclocked Core i7 | ||
4C/4T @ 3.8GHz | Core i5-4670K | ||
2C/4T @ 3.8GHz | Core i3-4370 |
Meanwhile on the iGPU side we have a range of Haswell and Kaveri processors from Intel and AMD respectively.
CPU: | Intel Core i7-4960X @ 4.2GHz |
Motherboard: | ASRock Fatal1ty X79 Professional |
Power Supply: | Corsair AX1200i |
Hard Disk: | Samsung SSD 840 EVO (750GB) |
Memory: | G.Skill RipjawZ DDR3-1866 4 x 8GB (9-10-9-26) |
Case: | NZXT Phantom 630 Windowed Edition |
Monitor: | Asus PQ321 |
Video Cards: | AMD Radeon R9 290X AMD Radeon R9 285 AMD Radeon HD 7970 NVIDIA GeForce GTX 980 NVIDIA GeForce GTX 750 Ti NVIDIA GeForce GTX 680 |
Video Drivers: | NVIDIA Release 349.90 Beta AMD Catalyst 15.200.1012.2 Beta |
OS: | Windows 10 Technical Preview (Build 10041) |
CPU: | AMD A10-7850K AMD A10-7700K AMD A8-7600 AMD A6-7400L Intel Core i7-4790K Intel Core i5-4690 Intel Core i3-4360 Intel Core i3-4130T Pentium G3258 |
Motherboard: | GIGABYTE F2A88X-UP4 for AMD ASUS Maximus VII Impact for Intel LGA-1150 Zotac ZBOX EI750 Plus for Intel BGA |
Power Supply: | Rosewill Silent Night 500W Platinum |
Hard Disk: | OCZ Vertex 3 256GB OS SSD |
Memory: | G.Skill 2x4GB DDR3-2133 9-11-10 for AMD G.Skill 2x4GB DDR3-1866 9-10-9 at 1600 for Intel |
Video Cards: | AMD APU Integrated Intel CPU Integrated |
Video Drivers: | AMD Catalyst 15.200.1012.2 Beta Intel Driver Version 10.18.15.4124 |
OS: | Windows 10 Technical Preview (Build 10041) |
113 Comments
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jtrdfw - Monday, April 6, 2015 - link
Actually it comes from terminator 2 when arnold is dropped into the molten metal.Zepid - Friday, March 27, 2015 - link
Not all 8GB is addressable. Only 3.5 GB of memory on the PS4 is, with 500MB extra of virtual in the wing. The Xbox One has 4GB addressable by the GPU, but a much weaker GPU.PlayStationBSD consumes a considerable amount of overhead, more than the HyperV Windows OS on the Xbox One.
Source: Console development at EA.
Laststop311 - Saturday, March 28, 2015 - link
yea ur right 4GB max for xbox one and 4GB max for ps4 but only if they tap into the extra 500MB offeredSamus - Saturday, March 28, 2015 - link
DirectX is an API, ie, software. There is nothing stopping Microsoft ans Sony from enabling DX12 in their consoles ans updating the devkits.DERSS - Saturday, March 28, 2015 - link
Sony obviously can not have anything to do with DX12, but nor they have to in the first place -- AMD's Mantle transitions to OpenGL's Vulkan project, so all games that are OpenGL-bases will be able to use it. Before that, AMD can help with using pure Mantle on PS4 as standalone thing as it is their GPU in there anyway.Gigaplex - Monday, March 30, 2015 - link
Sony could, if they managed to licence the API. There is no technical limitation preventing them from porting the DirectX API.akamateau - Thursday, April 30, 2015 - link
Actually SOny would have some difficulty as they are not using a Windows kernal as Microsoft is doing.PS4 uses Orbis OS derived from FreeBSD. DX12 obviously will not run on that though I am sure that Sony has that issue solved.
akamateau - Thursday, April 30, 2015 - link
Nah....DX12 is going into XBOX probably by October.http://www.vrworld.com/2015/04/29/directx-12-on-xb...
Current XBOX games will see a performance boost but the greatest boost will happen when XBOX game developers start writing DX12 games.
imaheadcase - Friday, March 27, 2015 - link
You also deal with the terrible UI in games for console users. Many small things in games add up to major complains for PC users.Frenetic Pony - Friday, March 27, 2015 - link
This is somewhat accurate. With DX12/Vulcan games should actually be easier to port, as explicit memory control, tight thread controls, and cheap draw calls are all assumed to be there when writing for consoles, which is then code beaten repeatedly like an abused step child to get it to play nice with DX11, in most part because it's not known what exactly the API and card are actually doing together.The end result should actually be that minimum requirements to play games, which crept up a lot over the last generation as the consoles were better understood but the PC version had to be brute forced into getting the API to behave, should creep up a lot less. But considering both the CPU and GPU of a high end PC are far beyond both consoles already, I'm not sure how much benefit end users will directly see. Maybe there will be setting to stop culling out small objects with distance, that would be an easy abuse of all those extra draw calls. But otherwise I can see the low to mid end benefitting a lot more than someone running crossfire 390s or something.