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
Frame Time Consistency & Recordings
Last, but not least, we wanted to also look at frame time consistency across Star Swarm, our two vendors, and the various APIs available to them. Next to CPU efficiency gains, one of the other touted benefits of low-level APIs like DirectX 12 is the ability for developers to better control frame time pacing due to the fact that the API and driver are doing fewer things under the hood and behind an application’s back. Inefficient memory management operations, resource allocation, and shader compiling in particular can result in unexpected and undesirable momentary drops in performance. However, while low-level APIs can improve on this aspect, it doesn’t necessarily mean high-level APIs are bad at it. So it is an important distinction between bad/good and good/better.
On a technical note, these frame times are measured within (and logged by) Star Swarm itself. So these are not “FCAT” results that are measuring the end of the pipeline, nor is that possible right now due to the lack of an overlay option for DirectX 12.
Starting with the GTX 980, we can immediately see why we can’t always write-off high-level APIs. Benchmark non-determinism aside, both DirectX 11 and DirectX 12 produce consistent frame times; one is just much, much faster than the other. Both on paper and subjectively in practice, Star Swarm has little trouble maintaining consistent frame times on the GTX 980. Even if DirectX 11 is slow, it is at least consistent.
The story is much the same for the R9 290X. DirectX 11 and DirectX 12 both produce consistent results, with neither API experiencing frame time swings. Meanwhile Mantle falls into the same category as DirectX 12, producing similarly consistent performance and frame times.
Ultimately it’s clear from these results that if DirectX 12 is going to lead to any major differences in frame time consistency, Star Swarm is not the best showcase for it. With DirectX 11 already producing consistent results, DirectX 12 has little to improve on.
Finally, along with our frame time consistency graphs, we have also recorded videos of shorter run-throughs on both the GeForce GTX 980 and Radeon R9 290X. With YouTube now supporting 60fps, these videos are frame-accurate representations of what we see when we run the Star Swarm benchmark, showing first-hand the overall frame time consistency among all configurations, and of course the massive difference in performance.
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james.jwb - Saturday, February 7, 2015 - link
Every single paragraph is completely misinformed, how embarrassing.Alexey291 - Saturday, February 7, 2015 - link
Yeah ofc it is ofc it is.inighthawki - Saturday, February 7, 2015 - link
>> There's no benefit for me who only uses a Windows desktop as a gaming machine.Wrong. Game engines that utilize DX12 or Mantle, and actually optimized for it, can increase the number of draw calls that usually cripples current generation graphics APIs. This leads to a large number of increased objects in game. This is the exact purpose of the starswarm demo in the article. If you cannot see the advantage of this, then you are too ignorant about the technology you're talking about, and I suggest you go learn a thing or two before pretending to be an expert in the field. Because yes, even high end gaming rigs can benefit from DX12.
You also very clearly missed the pages of the article discussing the increased consistency of performance. DX12 will have better frame to frame deltas making the framerate more consistent and predictable. Let's not even start with discussions on microstutter and the like.
>> Dx12 is not interesting either because my current build is actually limited by vsync. Nothing else but 60fps vsync (fake fps are for kids). And it's only a mid range build.
If you have a mid range build and limited by vsync, you are clearly not playing quite a few games out there that would bring your rig to its knees. 'Fake fps' is not a term, but I assume you are referring to unbounded framerate by not synchronizing with vsync. Vsync has its own disadvantages. Increase input lag and framerate halving by missing the vsync period. Now if only directx supported proper triple buffering to allow reduces input latency with vsync on. It's also funny how you insult others as 'kids' as if you are playing in a superior mode, yet you are still on a 60Hz display...
>> So why should I bother if all I do in Windows at home is launch steam (or a game from an icon on the desktop) aaaand that's it?
Because any rational person would want better, more consistent performance in games capable of rendering more content, especially when they don't even have a high end rig. The fact that you don't realize how absurdly stupid your comment is makes the whole situation hilarious. Have fun with your high overhead games on your mid range rig.
ymcpa - Wednesday, February 11, 2015 - link
Question is what do you lose from installing it? There might not be much gain initially as developers learn to take full advantage and they will be making software optimized for windows 7. However, as more people switch, you will start seeing games optimized for dx12. If you wait for that point, you will be paying for the upgrade. If you do it now you get it for free and I don't see how you will lose anything, other than a day to install the OS and possibly reinstall apps.Morawka - Friday, February 6, 2015 - link
Historically new DX release's have seen a 2-3 year adoption lag by game developers. Now, some AAA Game companies always throw in a couple of the new features at launch, the core of these engines will use DX 11 for the next few years.However with DX 12, The benifits are probably going to be to huge to ignore. Previous DX releases were new effects and rendering technologies. with DX 12, it effectively is cutting the minimum system requirements by 20-30% on the CPU side and probably 5%-10% on the GPU side.
So DX12 adoption should be much faster IMHO. But it's no biggie if it's not.
Friendly0Fire - Saturday, February 7, 2015 - link
DX12 also has another positive: backwards compatibility. Most new DX API versions introduce new features which will only work on either the very latest generation, or on the future generation of GPUs. DX12 will work on cards released in 2010!That alone means devs will be an awful lot less reluctant to use it, since a significant proportion of their userbase can already use it.
dragonsqrrl - Saturday, February 7, 2015 - link
"DX12 will work on cards released in 2010"Well, at least if you have an Nvidia card.
Pottuvoi - Saturday, February 7, 2015 - link
DX11 supported 'DX9 SM3' cards as well.DX12 will be similar, it will have layer which works on old cards, but the truly new features will not be available as hardware just is not there.
dragonsqrrl - Sunday, February 8, 2015 - link
Yes but you still need the drivers to enable that API level support. Every DX12 article I've read, including this one, has specifically stated that AMD will not provide DX12 driver support for GPU's prior to GCN 1.0 (HD7000 series).Murloc - Saturday, February 7, 2015 - link
I don't think so given that they're giving out free upgrades and the money-spending gamers who benefit from this the most will mostly upgrade, or if they're not interested in computers besides gaming, will be upgraded when they change their computer.