Nvidia announced and released Portal: Prelude RTX, a remaster of a 2008 mod. This update includes updated visuals, support for raytracing, DLSS 3 support, and is the first game to publicly use RTX I/O.
Raytracing and DLSS 3 are both rather self-explanatory as several games have come out featuring these technologies already. RTX I/O stands for RTX Input/Output and is a new way for your GPU to reduce the load times for large amounts...