Software, Cont: ShadowPlay and "Reason Flags"

Along with providing the game optimization service and SHIELD’s PC client, GeForce Experience has another service that’s scheduled to be added this summer. That service is called ShadowPlay, and not unlike SHIELD it’s intended to serve as a novel software implementation of some of the hardware functionality present in NVIDIA’s latest hardware.

ShadowPlay will be NVIDIA’s take on video recording, the novel aspect of it coming from the fact that NVIDIA is basing the utility around Kepler’s hardware H.264 encoder. To be straightforward video recording software is nothing new, as we have FRAPS, Afterburner, Precision X, and other utilities that all do basically the same thing. However all of those utilities work entirely in software, fetching frames from the GPU and then encoding them on the CPU. The overhead from this is not insignificant, especially due to the CPU time required for video encoding.

With ShadowPlay NVIDIA is looking to spur on software developers by getting into video recording themselves, and to provide superior performance by using hardware encoding. Notably this isn’t something that was impossible prior to ShadowPlay, but for some reason recording utilities that use NVIDIA’s hardware H.264 encoder have been few and far between. Regardless, the end result should be that most of the overhead is removed by relying on the hardware encoder, minimally affecting the GPU while freeing up the CPU, reducing the amount of time spent on data transit back to the CPU, and producing much smaller recordings all at the same time.

ShadowPlay will feature multiple modes. Its manual mode will be analogous to FRAPS, recording whenever the user desires it. The second mode, shadow mode, is perhaps the more peculiar mode. Because the overhead of recording with the hardware H.264 encoder is so low, NVIDIA wants to simply record everything in a very DVR-like fashion. In shadow mode the utility keeps a rolling window of the last 20 minutes of footage, with the goal being that should something happen that the user decides they want to record after the fact, they can simply pull it out of the ShadowPlay buffer and save it. It’s perhaps a bit odd from the perspective of someone who doesn’t regularly record their gaming sessions, but it’s definitely a novel use of NVIDIA’s hardware H.264 encoder.

NVIDIA hasn’t begun external beta testing of ShadowPlay yet, so for the moment all we have to work from is screenshots and descriptions. The big question right now is what the resulting quality will be like. NVIDIA’s hardware encoder does have some limitations that are necessary for real-time encoding, so as we’ve seen in the past with qualitative looks at NVIDIA’s encoder and offline H.264 encoders like x264, there is a quality tradeoff if everything has to be done in hardware in real time. As such ShadowPlay may not be the best tool for reference quality productions, but for the YouTube/Twitch.tv generation it should be more than enough.

Anyhow, ShadowPlay is expected to be released sometime this summer. But since 95% of the software ShadowPlay requires is also required for the SHIELD client, we wouldn’t be surprised if ShadowPlay was released shortly after a release quality version of the SHIELD client is pushed out, which may come as early as June alongside the SHIELD release.

Reasons: Why NVIDIA Cards Throttle

The final software announcement from NVIDIA to coincide with the launch of the GTX 780 isn’t a software product in and of itself, but rather an expansion of NVIDIA’s 3rd party hardware monitoring API.

One of the common questions/complaints about GPU Boost that NVIDIA has received over the last year is about why a card isn’t boosting as high as it should be, or why it suddenly drops down a boost bin or two for no apparent reason. For technically minded users who know the various cards’ throttle points and specifications this isn’t too complex – just look at the power consumption, GPU load, and temperature – but that’s a bit much to ask of most users. So starting with the recently released 320.14 drivers, NVIDIA is exposing a selection of flags through their API that indicate what throttle point is causing throttling or otherwise holding back the card’s clockspeed. There isn’t an official name for these flags, but “reasons” is as good as anything else, so that’s what we’re going with.

The reasons flags are a simple set of 5 binary flags that NVIDIA’s driver uses to indicate why it isn’t increasing the clockspeed of the card further. These flags are:

  • Temperature Limit – the card is at its temperature throttle point
  • Power Limit – The card is at its global power/TDP limit
  • Voltage Limit – The card is at its highest boost bin
  • Overvoltage Max Limit – The card’s absolute maximum voltage limit (“if this were to occur, you’d be at risk of frying your GPU”)
  • Utilization Limit – The current workload is not high enough that boosting is necessary

As these are simple flags, it’s up to 3rd party utilities to decide how they want to present these flags. EVGA’s Precision X, which is NVIDIA’s utility of choice for sampling new features to the press, simply records the flags like it does the rest of the hardware monitoring data, and this is likely what most programs will do.

With the reason flags NVIDIA is hoping that this will help users better understand why their card isn’t boosting as high as they’d like to. At the same time the prevalence of GPU Boost 2.0 and its much higher reliance on temperature makes exposing this data all the more helpful, especially for overclockers that would like to know what attribute they need to turn up to unlock more performance.

Software: GeForce Experience, Out of Beta Our First FCAT & The Test
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  • lukarak - Friday, May 24, 2013 - link

    1/3rd FP32 and 1/24th FP32 is nowhere near 10-15% apart. Gaming is not everything. Reply
  • chizow - Friday, May 24, 2013 - link

    Yes fine cut gaming performance on 780 and Titan down to 1/24th and see how many of these you sell at $650 and $1000. Reply
  • Hrel - Friday, May 24, 2013 - link

    THANK YOU!!!! WHY this kind of thing isn't IN the review is beyond me. As much good work as Nvidia is doing they're pricing schemes, naming schemes and general abuse of customers has turned me off of them forever. Which convenient because AMD is really getting their shit together quickly. Reply
  • chizow - Saturday, May 25, 2013 - link

    Ryan has danced around this topic in the past, he's a pretty straight shooter overall but it goes without saying why he isn't harping on this in his review. He has to protect his (and AT's) relationship with Nvidia to keep the gravy train flowing. They have gotten in trouble with Nvidia in the past (sometime around the "not covering PhysX enough" fiasco, along with HardOCP) and as a result, their review allocation suffered.

    In the end, while it may be the truth, no one with a vested interest in these products and their future success contributing to their livelihoods wants to hear about it, I guess. It's just us, the consumers that suffer for it, so I do feel it's important to voice my opinion on the matter.
    Reply
  • Ryan Smith - Sunday, May 26, 2013 - link

    While you are welcome to your opinion and I doubt I'll be able to change it, I would note that I take a dim view towards such unfounded nonsense.

    We have a very clear stance with NVIDIA: we write what we believe. If we like a product we praise it, if we don't like a product we'll say so, and if we see an issue we'll bring it up. We are the press and our role is clear; we are not any company's friend or foe, but a 3rd party who stakes our name and reputation (and livelihood!) on providing unbiased and fair analysis of technologies and products. NVIDIA certainly doesn't get a say in any of this, and the only thing our relationship is built upon is their trusting our methods and conclusions. We certainly don't require NVIDIA's blessing to do what we do, and publishing the truth has and always will come first, vendor relationships be damned. So if I do or do not mention something in an article, it's not about "protecting the gravy train", but about what I, the reviewer, find important and worth mentioning.

    On a side note, I would note that in the 4 years I have had this post, we have never had an issue with review allocation (and I've said some pretty harsh things about NVIDIA products at times). So I'm not sure where you're hearing otherwise.
    Reply
  • chizow - Monday, May 27, 2013 - link

    Hi Ryan I respect your take on it and as I've said already, you generally comment on and understand more about the impact of pricing and economy more than most other reviews, which is a big part of the reason I appreciate AT reviews over others.

    That being said, much of this type of commentary about pricing/economics can be viewed as editorializing, so while I'm not in any way saying companies influence your actual review results and conclusions, the choice NOT to speak about topics that may be considered out of bounds for a review does not fall under the scope of your reputation or independence as a reviewer.

    If we're being honest here, we're all human and business is conducted between humans with varying degrees of interpersonal relationships. While you may consider yourself truthful and forthcoming always, the tendency to bite your tongue when friendships are at stake is only natural and human. Certainly, a "How's your family?" greeting is much warmer than a "Hey what's with all that crap you wrote about our GTX Titan pricing?" when you meet up at the latest trade show or press event. Similarly, it should be no surprise when Anand refers to various moves/hires at these companies as good/close friends, that he is going to protect those friendships where and when he can.

    In any case, the bit I wrote about allocation was about the same time ExtremeTech got in trouble with Nvidia and felt they were blacklisted for not writing enough about PhysX. HardOCP got in similar trouble for blowing off entire portions of Nvidia's press stack and you similarly glossed over a bunch of the stuff Nvidia wanted you to cover. Subsequently, I do recall you did not have product on launch day and maybe later it was clarified there was some shipping mistake. Was a minor release, maybe one of the later Fermi parts. I may be mistaken, but pretty sure that was the case.
    Reply
  • Razorbak86 - Monday, May 27, 2013 - link

    Sounds like you've got an axe to grind, and a tin-foil hat for armor. ;) Reply
  • ambientblue - Thursday, August 8, 2013 - link

    Well, you failed to note how the GTX 780 is essentially kepler's version of a GTX 570. It's priced twice as high though. The Titan should have been a GTX 680 last year... its only a prosumer card because of the price LOL. that's like saying the GTX 480 is a prosumer card!!! Reply
  • cityuser - Thursday, May 23, 2013 - link

    whatever Nvidia do, it never improve their 2D quality, I mean , look at what nVidia will give you at BluRay playing, the color still dead , dull, not really enjoyable.
    It's terrible to use nVidia to HD home cinema, whatever setting you try.
    Why nVidia can ignore this? because it's spoiled.
    Reply
  • Dribble - Thursday, May 23, 2013 - link

    What are you going on about?

    Bluray is digital, hdmi is digital - that means the signal is decoded and basically sent straight to the TV - there is no fiddling with colours, or sharpening or anything else required.
    Reply

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