DLSS 3.5 Tested: Ray Reconstruction In Cyberpunk 2077 Helps Path Tracing Shine
NVIDIA's DLSS, though, really has nothing to do with that. Instead, "Deep Learning Super Sampling" has evolved into a suite of technologies that attempt to improve the gaming experience using AI. The original DLSS is now known as "Super Resolution", and it involves temporally jittering a lower-resolution initial render to generate a higher-resolution output render that looks more convincing than traditional upscalers. The 1.0 version required AI models trained for each game, but current iterations of DLSS Super Resolution (SR) are universal.
With the launch of the GeForce RTX 4000 series cards and the Ada Lovelace architecture, NVIDIA introduced a new DLSS feature that requires a GPU from that series: Frame Generation (FG). Heavily marketed along with the DLSS 3 version number, a lot of people conflate "DLSS 3" with the Frame Generation technology, but that's not exactly accurate; NVIDIA itself recommends using the feature names à la carte instead of talking about version numbers.
We bring that up because DLSS 3.5 is here, and it brings along another new feature: Ray Reconstruction. Despite the version number increase over Frame Generation, you don't need to have an Ada Lovelace GPU to take advantage of Ray Reconstruction, but you're probably going to want one. We've already written quite a bit about Ray Reconstruction, so we're not going to fully re-tread all of that ground here. You can hit up our previous coverage for the complete details on exactly what Ray Reconstruction is, what it's doing, and why it was created.
The short version is that the initial graphics produced through real-time ray-tracing are very noisy because we cast a relatively low number of rays per pixel. You need smart denoisers to turn that image into the familiar game screenshots you've already been looking at. Cyberpunk 2077 uses as many as five separate denoisers per frame, and these filters have their own performance costs and limitations.
Using resolution upscaling is almost a requirement of playing in Cyberpunk 2077's path-traced graphics mode. That's because the performance cost of ray-traced effects and particularly path-tracing (or so-called "full ray-tracing") scale in a quadratic way with render resolution. Even a mighty GeForce RTX 4090 struggles to maintain 30 FPS at native 4K in Cyberpunk 2077 with path-tracing on without DLSS upscaling.
The issue comes in that producing a high-quality image using denoisers needs as many samples as possible. When you reduce the render resolution as you do when using DLSS Super Resolution, you reduce the number of samples available to the denoiser. This results in an excessively-smoothed appearance where fine details get smudged out by the denoisers because they can't tell the difference between those fine details and path-traced noise.
NVIDIA's solution to this problem is to simply use the same AI for both upscaling and denoising. In other words, DLSS 3.5 adds denoising for path tracing to the DLSS AI's bag of tricks. If you have a compatible graphics card, which is any GeForce RTX GPU, then DLSS Ray Reconstruction will be toggled on automatically when you enable the RT: Overdrive graphics preset or manually enable the Path-Tracing Technology Preview option.
That's right: DLSS Ray Reconstruction can only used if you're playing in path-traced mode. That means that this new feature isn't applicable to anyone who isn't comfortable with the performance of that mode on their system. The official requirements recommend a GeForce RTX 4080 for the RT Overdrive mode, but that's also to achieve 60 FPS in 4K resolution. Practically speaking, it is possible to achieve playable performance on something as modest as a GeForce RTX 3060 Ti, but anything below that is going to struggle no matter what.
You also have to be using DLSS Super Resolution, which means that Ray Reconstruction can't currently be used while rendering at native resolution. However, NVIDIA says that it is working on getting DLSS RR working alongside DLAA. That's essentially DLSS running at native resolution, turning it into a very powerful temporal anti-aliasing solution.
So the ultimate question is: does it work? Well, sure it does. DLSS Ray Reconstruction offers exactly what NVIDIA said it would: improved quality for lighting and reflections, particularly in terms of fine details. Just as DLSS Super Resolution makes your game look like it's being rendered in a higher resolution than it is, DLSS Ray Reconstruction makes the lighting look more like it's being de-noised in your native resolution.
The result is some amazing detail added to characters and fine objects. Places that should have been shadowed before now actually are, and details on characters in harsh lighting no longer get lost in dark shadows or overbright highlights. The lighting overall has a brighter and more colorful character to it, although in some scenes you do lose a bit of the moody contrast that the original hand-tuned denoisers seem to have been intentionally set up for.
We'd be remiss if we didn't note that Ray Reconstruction is not a one-click fix for all of the faults of path-traced rendering. Because we're relying so heavily on temporal technologies here—techniques that pull forward data sampled from previous frames-you can still see temporal "ghosting" artifacts behind NPCs and objects. These aren't unique to Ray Reconstruction at all, but it does little or nothing to resolve them.
There are a few other visual regressions with DLSS RR, too. Certain objects in the game world, particularly those that glow or are otherwise brightly-colored, are already known to leave trails behind in path-traced mode. DLSS RR can amplify these trails to an exaggerated degree. We also noticed an issue where LOD pop-ins create large black spots on the screen when they change, which again is always present in path-traced mode but seems much more noticeable with Ray Reconstruction enabled.
These flaws don't ruin Ray Reconstruction, though. If anything, we'd simply say they detract from the overall gains, because we think Ray Reconstruction taken as a whole is a net gain for image quality. Your author prefers the darker and moodier lighting of the original denoisers in some scenes, like the interior of Misty's Esoterica, but in conversations and anytime you're looking at characters close-up, the extra detail in the path-traced render is absolutely worth some occasional weirdness.
The lighting on Jackie's face is much more detailed with DLSS RR enabled.
But what about performance? You'll notice that the usual HotHardware performance graph isn't present in this post. That's because Ray Reconstruction has almost no effect on performance. We've played the game for about eight hours so far since the 2.0 update, and there definitely have been a few places where DLSS RR has a measurable performance impact, but even in the best cases it's very small. In the game's canned benchmark, it makes absolutely no difference on performance.
So with the possibility of slightly-improved performance plus the benefit of sharper and clearer lighting and reflections, should you enable Ray Reconstruction in Cyberpunk 2077? Almost assuredly. Not everyone will like the way it changes the game's looks, because it absolutely does change the visual aesthetic of Cyberpunk 2077 significantly. On balance, though, it makes for a richer and more detailed presentation that we think ultimately vindicates NVIDIA's work.
Of course, this is just one game. NVIDIA believes that path-tracing is the future of computer graphics, and DLSS Ray Reconstruction is likely to appear in every future path-traced game. Next up on the docket is Alan Wake 2, releasing on October 27th, but NVIDIA's added DLSS 3.5 support to Unreal Engine 5 too, so we may start seeing it added to more games rather rapidly. Here's looking ahead to the glorious path-traced future.
