Microsoft has some exciting news to share from GDC 2019 that will improve gaming performance. In DirectX 12, Microsoft is introducing Variable Rate Shading. The new API allows for more effective use of GPU resources so that high detail areas are rendered clearly and less time can be spent on screen areas that have less need for fine tuning.
When calculating pixel colors in DirectX, shaders are the workhorse element doing that process. The shading rate is how quickly shaders can be called upon to produce more pixel data.