In spring, Nvidia announced a new version of the DLSS 4.5 gaming upscaling technology coming in August, promising improved output quality, through settling a debt of sorts: The DLSS 4.5 technology eliminated the Ray Reconstruction technology (originally introduced as part of DLSS 3.5), so you lost access to it when enabling DLSS 4.5. Now this incompatibility has been solved, and Ray Reconstruction is also coming to DLSS 4.5.
DLSS 4.5 upscaling introduced a transformer-based AI model that’s more advanced (but also more demanding and slower on older graphics cards) and is supposed to increase visual quality in games. However, after its release, there was one drawback to the new model that was actually not discussed much: DLSS 4.5 was incompatible with Ray Reconstruction, which links upscaling with the denoising performed during ray-traced rendering.
Ray Reconstruction is a technique that tries to prevent denoising from degrading upscaling quality by allowing the upscaling process (which is running later) to also use image data that the denoiser has blurred or otherwise degraded—the two steps are thus interconnected instead of being isolated (in which case the upscaling would be working just with the data output by the denoiser). This should help improve the quality of reflections and details in some parts of the image—for example, in shadows and similar areas.
After the release of DLSS 4.5, however, the situation was that if you wanted to have Ray Reconstruction enabled, you had to revert the game to the older DLSS 4 upscaling model. There was no 4.5 generation neural network that was compatible. You therefore could not have the benefits of both upscaling technologies at the same time.
DLSS 4.5 Ray Reconstruction
Now, during Gamescom, Nvidia has finally made available the update announced at the turn of May and June, with which a DLSS 4.5 model that supports Ray Reconstruction is finally being released. It will therefore no longer be necessary to revert DLSS upscaling to an older version. In this new version, Nvidia directly uses the designation DLSS 4.5 Ray Reconstruction, although, as mentioned, this is not an entirely new feature, but merely the reactivation of technology that was already available in DLSS 3.5 and DLSS 4.
In this version of DLSS, the ray tracing denoiser is supposed to deliver higher quality—according to Nvidia, it performs up to 35% more compute operations and its AI model has 20% more parameters. Performance supposedly should not deteriorate significantly—Nvidia says it is “similar” to that of older DLSS 4.5 versions, which may still entail some slowdown.
The DLSS 4.5 Ray Reconstruction model should also once again be freshly re-trained, using a larger training-data corpus than previous versions, and the entire upscaling technology should include various other incremental changes that should contribute to better visual quality of the final result. Or at least that is what Nvidia promises. In addition, this new version introduces several new configuration parameters that game developers will be able to fine-tune when integrating DLSS 4.5 into individual titles.
The hardware requirements for the technology remain the same. DLSS 4.5 therefore still works on Nvidia GeForce RTX graphics cards starting with the 2000 generation (Turing), including the Ray Reconstruction feature.
For now as a beta
To use DLSS 4.5 Ray Reconstruction, you need to download the latest GeForce 580.88 WHQL graphics drivers and the Nvidia App. Games will not yet use this new version of the DLSS 4.5 model automatically; you have to go to the “About” section in the Nvidia App settings and check the option to enable access to experimental and beta features (DLSS 4.5 Ray Reconstruction presumably still falls into this category).
You can then manually enable the new version of DLSS for individual games or globally via the “DLSS Override” option, where in the AI model settings you need to select “Preset F,” which is what the new feature is hidden under (unfortunately, this is not a particularly intuitive designation).
For now, DLSS 4.5 Ray Reconstruction is therefore not active “out of the box,” and also, Nvidia currently lists only thirty games in which it can be enabled using DLSS Override. They are as follows:
Over time, however, their number should increase, and the DLSS 4.5 Ray Reconstruction model will probably gradually become included in games by default as well. But Nvidia has not yet said when this feature will leave the beta stage.
English translation and edit by Jozef Dudáš
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