While Cyberpunk 2077 already implemented Nvidia RTX with ray-traced shadows, reflections, and global illumination, although from a small and limited number of light sources, the latest Ray Tracing: Overdrive Mode will bring the so-called full ray tracing, which, according to Nvidia, "models the properties of light from a virtually unlimited number of emissive sources, delivering physically correct shadows, reflections and global illumination on all objects."
The biggest update is the Nvidia RTX Direct Illumination (RTXDI), a free SDK that has been recently released to all developers, which allows them to replicate the appearance of light in scenes with numerous light sources. For example, in Cyberpunk 2077 screenshots provided, each neon sign, street lamp, LED billboard, car headlight, and other source of light are now ray-traced, emitting lighting on all objects, including walls, passing cars, and pedestrians.
With full ray tracing and RTXDI, all light sources also cast physically correct soft shadows, and even global illumination gets path traced. The game, which previously used several rendering techniques including Screen Space Reflections, Screen Space Ambient Occlusion, and the existing GI solutions, are now replaced by a single unified algorithm that delivers more accurate lighting of scenes and objects.
Thanks to that same unified ray-traced pipeline, there is no need for per-scene tweaking, saving time for developers and visual artists, while improving image quality, immersion, and realism.
Of course, those things come at a price, and full ray tracing requires some serious hardware, and that is where Nvidia comes in with the recently introduced Shader Execution Reordering (SER), which speeds up those incoherent workloads, Real-Time Denoisers (NRD), which improves both performance and image quality, and, of course, DLSS 3, which certainly helps in pulling a bit more frame rates. Nvidia recommends Geforce RTX 40 series for Cyberpunk 2077's Ray Tracing: Overdrive Mode, mostly due to support for SER and DLSS 3.
"Here at CD PROJEKT RED we are very proud to be technology innovators, and DLSS 3 gives us meaningful performance gains to tackle the addition of even higher levels of ray tracing to deliver a visually rich experience for our gamers." - Jakub Knapik, VP, Global Art Director, CD PROJEKT RED