The Xbox Series X will use Microsoft's DirectX 12 Ultimate graphics technology, meaning it'll be easier for developers to optimize games for the Xbox and PC platforms at the same time.
Revealed in a developer blog (via The Verge), the new API is guaranteed to support DirectX Raytracing, Variable Rate Shading, Mesh Shaders and Sampler Feedback, ensuring that your Xbox or PC graphics card will be ready to display the latest games in their full glory while running efficiently.
This new standard is not a huge leap compared to DirectX 12, but there are some useful improvements. Ray tracing can now be done on the GPU only instead of requiring help from the CPU, allowing more efficient performance while still giving more realistic lighting, shadows and reflections.
Mesh shaders allow for distant objects to be drawn with fewer polygons, while variable rate shading allows objects in the same scene to have differing levels of color detail, both using the platform's performance where it's needed.
Sampler feedback shades objects that don't change as much, like distant buildings, again allowing the GPU to put its effort to use elsewhere, such as increasing the framerate.
All of this is now easier for developers to add into their games via DirectX 12 Ultimate, therefore making them look better on compatible platforms like the Xbox Series X. It may take some time for games using this tech to be released, but the point of having compatible hardware is to make sure you're futureproof.
An added benefit to PC and Xbox Series X being on the same graphics platform is that upcoming PC games could become very easy to port to Xbox. As such, you may see an even greater influx of third-party and PC-centric titles come to the Xbox Series X.
For PC gamers, DirectX 12 Ultimate has been announced to have support on both Nvidia and AMD hardware, albeit only on more recent products for the latter. AMD has said the standard will work with its RDNA 2 architecture, the design that underpins both the Xbox Series X and the PS5. As such, DirectX 12 Ultimate could theoretically work on PS5, but we'll have to wait and see if Microsoft allows that to happen.