Various other calculations for things like weather and particle effects all consume resources. Textures are placed on 3D models which will consume GPU resources to render. Each texture is an image that will consume memory. Why is it that some games can run on a perfectly on the PS4, but require crazy specs on PC? When it comes to hardware requirements for games, there are a lot of factors that are going to use up system resources.
Video game hardware requirements can often be confusing and a tricky thing to understand.
