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.

Mid Quality Performance First Thoughts
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  • OrphanageExplosion - Tuesday, February 10, 2015 - link

    Sony already has its low-level API, GNM, plus its DX11-a-like GNMX, for those who need faster results, easier debugging, handling of state etc.
  • Gigaplex - Monday, February 9, 2015 - link

    The consoles already use bare metal APIs. This will have minimal impact for consoles.
  • Bill McGann - Tuesday, February 10, 2015 - link

    D3D11.x is garbage compared to GNM (plus the XbOne HW is garbage compared to the PS4). The sad fact is that the XbOne desperately needs D3D12(.x) in order to catch up to the PS4.
  • Notmyusualid - Monday, February 9, 2015 - link

    Hello all... couldn't find any MULTI-GPU results...

    So here are mine:

    System: M18x R2 3920XM (16GB RAM 1866MHz CAS10), Crossfire 7970Ms.
    Test: Star Swarm Perf demo RTS, all Extreme setting.
    Ambient temp 31C, skype idling in background, and with CPU ALL at stock settings:

    Mantle: fps max 99.03 min 9.65 AVG 26.5
    DX11: fps max 141.56 min 3.26 AVG 11.6

    CPU at 4.4GHz x 4 cores, fans 100%, skype in background again:

    Mantle: fps max 51.03 min 7.26 AVG 26.2 - max temp 94C
    DX11: fps max 229.06 min 3.6 AVG 12.3 - max temp 104C + thus cpu throtteled at 23%.

    So I guess there are good things coming to PC gamers with multi-gpu's then. Alas, being a mere mortal, I've no access to DX12 to play with...

    Anyone care to offer some SLI results in return?
  • lamebot - Monday, February 9, 2015 - link

    I have been reading this article page by page over the weekend, giving myself time to take it in. The frame times from each vendor under DX11 is very interesting. Thank you for a great, in depth article! This is what keeps me coming back.
  • ChristTheGreat - Monday, February 9, 2015 - link

    Can it be only a WIndows 10 Driver problem or optimisation for these result with the R9 290/X? On windows 8.1, 4770k 4.3ghz and R9 290 1100/1400, I do 40avg D3D11 and 66avg Mantle.. Scenario: follow, Detail: extreme...
  • ChristTheGreat - Monday, February 9, 2015 - link

    Oh well, I saw that you guys use the Asus PQ321, so running in 3 840 x 2 160?
  • Wolfpup - Monday, February 9, 2015 - link

    Good, can Mantle go away now? The idea of moving BACK to proprietary APIs is a terrible one, unless the only point of it was to push Microsoft to make these fixes in Direct X.

    "Stardock is using the Nitrous engine for their forthcoming Star Control game"

    I didn't know! This is freaking awesome news. I love love love Star Control 2 on the 3DO. Liked 1 on the Genesis too, but SC2 on the 3DO (which I think is better than the PC version) is not unlike Starflight-and somewhat like Mass Effect.
  • Wolfpup - Monday, February 9, 2015 - link

    Forgot to mention... I also think AMD needs to worry about making sure their DirectX/Open GL drivers are flawless across years of hardware before wasting time on a proprietary API too...
  • lordken - Monday, February 9, 2015 - link

    Sorry but are you just amd hater or something?
    imho AMD did great thing with mantle and possibly pushed M$ to come with DX12 (or not we will never know). But that aside how about you think about some advantages mantle has?
    I think that when they bring it to linux (they said they would, not sure about current status) that will be nice advantage as I guess native api would work better than wine etc. With more recent games (thanks to new engines) comming to linux would probably benefit more if they would run on mantle.

    And nonetheless how about ppl that wont move to Win10 (for whatever reason)? Mantle on Win7/8 would still be huge benefit for such ppl. Not to mention that there will be probably more games with mantle than with DX12 in very close feature.
    Plus if they work out console & pc mantle aspect it could bring better console ports to PC, even if game devs would be lazy to do proper optimalization mantle should pretty much eliminate this aspect (though only for amd gpu).
    But either way I dont see much reason why should mantle go. I mean once it is included in all/most bigger engines (already in cryengine,frostbite,unreal) and it works what reason would be to trash something that is usefull?

    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)

    PS:What about amd drivers? They are fine imho, never had problem in last years. (you see personal experience is not a valid argument)

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