What is NVIDIA DLSS, and How Will It Make Ray Tracing Faster?

At the presentation of NVIDIA on CES 2019, the company introduced a new technology called DLSS. In the demos, this almost eliminates the performance hit in games that allow new fantasy ray throwing graphics on RTX cards. But how does it work?

What is DLSS?

DLSS stands for "super-sampling in deep learning". This idea has two parts, but let's focus on the second one: super-sampling.

Super-sampling is something you can do on your machine right now with lots of games. This makes the game at a higher resolution than your monitor can handle. This sounds strange, but it can help alleviate some of the most difficult contours of polygonal graphics. NVIDIA and AMD cards already support this technology, like some PC games. To learn more about super sampling, see this article.

Let's move on to the "deep learning" part. In-depth learning is a pretty blurry term: it basically means tons and tons of calculations run on very powerful hardware according to a process that improves with time. Some apps call this "Artificial Intelligence" (AI), but it is an improper term; the system does not learn in the human sense of the word, it improves more and more during a repetitive process.

The NVIDIA DLSS system performs oversampling on a specific game over and over again on the graphics cards of its huge data centers. It calculates the best ways to apply the oversampling technique to a game with a repetitive treatment on the visual elements of this game – the polygons and textures that make up what you see on your screen. The "deep learning" part of the process comes into play here; the system learns as much as possible about the game's appearance and how to improve it.

Combine super-sampling to get smoother polygon lines and textures with in-depth learning to apply general improvements to a game and you get DLSS. The image enhancement techniques, already calculated by NVIDIA data centers, are applied on the fly via Tensor processing cores of the RTX card.

NVIDIA engineers explained the process and demonstrated it, using a graphic test done at CES. The improvements over a non-DLSS configuration were impressive, with textures and polygons smoother and more uniform. This was true even when the DLSS machine was rendering its graphics with a lower output (1080p) than the non-DLSS (1440p) machine.

How does this make a game faster?

The DLSS system applies general enhancements to the visual elements of a game, especially if you run the game with enhanced NVIDIA ray tracing enabled. The ray tracing, introduced for the first time with RTX series cards, allows for more accurate reflections, shadows and light scattering, with amazing results. We have already covered the ways that ray tracing can enhance the visual effects of the game.

Unfortunately, ray tracing also increases the load on the GPU. The charge is so high that many games fall below the desired 60 fps, even when you use the latest NVIDIA cards and high-end components in the rest of the PC.

The use of precomputed DLSS enhancements, which NVIDIA data center RTU GPUs have already begun, has smoothed the performance of RTX-enabled games. In his CES demo, a game with ray tracing and DLSS activated was played in a frame or two of the game without any ray tricks activated. To put it simply: DLSS allows games to run much faster with more sophisticated lighting effects.

NVIDIA tells us that the process is not perfect: DLSS activation might erase textures or geometry in rare cases. But overall, the improvement is spectacular and worthwhile if it's an option.

Can my card use DLSS?

DLSS is a feature of NVIDIA's proprietary Tensor processing core, present on the Turing GPU architecture in the new RTX cards. If you have a GeForce RTX graphics card, you can use DLSS. If you do not do it, you can not. Thus, the still popular GeForce GTX 900 and 1000 cards can not take advantage of DLSS technology.

Do I need a web connection to use it?

No. While the DLSS process uses vast amounts of cloud computing hardware – huge NVIDIA server farms with industrial versions of RTX graphics cards – the process runs on your local PC once the system is set up and activated. Just make sure you use the latest drivers.

Is my game DLSS compatible?

The problem is that DLSS deep learning requires months of processing in NVIDIA data centers before it can be applied to PC gaming. So for each new game, NVIDIA has to run its gigantic GPU bays for a long time before DLSS is ready.

Once heavy tasks are completed, NVIDIA will update its GPU drivers and activate DLSS on new games. The developer will then be able to enable it by default or allow it as a graphical option in the settings menu. Since the deep learning system must examine the geometry and textures of each game individually to improve the performance of that specific game, there is no way around this "one game at a time" approach. It will go faster as NVIDIA improves it – possibly reducing play time in weeks or days – but for now, it takes a while.

At the time of writing this article (January 2019), only one game has DLSS that you can activate on a home gaming PC: Final Fantasy XV. Even though it's in beta form and only works on the highest resolutions. Early tests showed that the number of framerates increased by 10-15 FPS, about the same amount you lose by turning on RTX ray tracing in other games. (Currently, FFXV does not support ray tracing, so the DLSS boost is not applied where it's really needed.)

NVIDIA has announced a list of other existing and upcoming games that will eventually support the DLSS system. It is likely that the company is operating its data centers at full capacity to prepare it. Currently, NVIDIA has confirmed future DLSS support for twenty-five games, with notable titles like Hellblade: Senua's Sacrifice, ARK: Survival Evolved, Atomic Heart, Hitman 2, Mechwarrior V, Playerunknown's Battlegrounds, Shadow of the Tomb Raider and We Happy Few. At CES, the company also announced that Battlefield V and the upcoming anthem would support the DLSS protocol – the latter could even have the processing done before being available.

The games that will support both RTX exclusive tracing effects and DLSS performance enhancing system are a short list:

Anthem
Atomic heart
Battlefield V
MechWarrior V
Shadow of the Tomb Raider
Justice online
JX3

Naturally, this list will grow as developers become more familiar with ray tracing, NVIDIA will soften and speed up its DLSS computing process, and PC gamers will require access to all the features of their RTX branded graphics cards.

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