Xbox Series X supports all RDNA 2 features. One of the features that should bring significant performance boost in games is Mesh Shaders.
"I’m sure you have heard that the Xbox Series X supports all RDNA 2 & Direct X 12 Ultimate features. One of the features that should bring a significant performance boost in games is Mesh Shaders.
We have yet to see games utilizing Mesh Shading and we are not sure what kind of performance increase this will bring in games. However, there are benchmarks that present potential gains already. One of the most exciting demos showcasing how this new technology works is the “Advanced Mesh Shaders” presentation by Martin Fuller. He runs a program on an Xbox Series X dev kit with Mesh Shading enabled in real-time. When he enables Advanced Culling it cuts the rendering time by half."
So apparently there is a function built into the hardware of the series x / s, this function is for a next-gen only feature called mesh shaders which will double the performance of the Xbox series x / s. From what I understand there are no games that you can play right now that utilize mesh shaders because the studios have to rebuild their game engines for it. I think the first games to utilize mesh shaders are coming out next year. It doesn't look like the PS5 is going to utilize mesh shaders as I believe it was something Microsoft developed. I firmly believe we're going to see a huge leap in graphics once the studios rebuild their game engines to take advantage of all the next gen features.