Nvidia's DLSS Technology Analyzed: It All Starts With Upscaling

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Analysis of the Rendering Pipeline

Really, none of the performance-oriented data is new. We already did quite a bit of testing with DLSS for the GeForce RTX 2080 Ti, 2080, and 2070 reviews, after all. So, it was time to pull out the heavy artillery: Nvidia's Nsight Graphics analyzer. The software is described as "a standalone developer tool that enables you to debug, profile, and export frames built with Direct3D (11, 12, DXR), Vulkan (1.1, NVX Vulkan Raytracing Extension), OpenGL, OpenVR, and the Oculus SDK." In this project, we're using it to break down all of the rendering steps.

Rendering in Final Fantasy XV

There are approximately 50,000 rendering steps in the Final Fantasy XV demo, some of which we illustrate in the following album. But one highlight stands out above the rest: at 4K with DLSS enabled, all of the rendering steps are performed at QHD. It's only the penultimate image that jumps to 4K, right before the menu is overlaid.

Also interesting, when the rendering is finished in QHD, the graphics card applies anti-aliasing just before going into 4K. We don't know the nature of this anti-aliasing step, but we suspect that it's simply TAA for two reasons. First, it's ineffective on the first frame of a new scene, similar to temporal anti-aliasing. Second, DLSS appears to only be compatible with games (or demos for now) that support TAA.

Rendering in Infiltrator

The Infiltrator demo appears to be more complex than Final Fantasy XV, reaching as many as 100,000 rendering steps for some frames. Still, the result is the same: all of the steps are performed at a lower resolution before being output to a higher target resolution at the very end.

At 4K, we again see DLSS operate at QHD behind the scenes. Switching to QHD with DLSS shows the technology working at 1708x960, or exactly two-thirds of the desired resolution.

Given our results, it's clear that DLSS first renders at a lower resolution: 2560 x 1440 for a 4K output and 1708 x 960 for a QHD target. The ratio is always 150% between the base and target.