Microsoft revealed at the BUILD conference that it's working on DirectX 11.2 and that this new API will introduce Tiled Resources, a new feature that will enable game developers to pack a lot more detail by allowing your main system RAM to be used alongside your graphics card's RAM to enhance texture detail. Unfortunately, it appears this feature will be exclusive to the Xbox One and DirectX 11.2, which will only be released for Windows 8.1. Details about other changes in DirectX 11.2 can be found over here.
Windows 8.1 Preview includes a new Direct3D feature called tiled resources, which exposes a limited virtual graphics memory model to apps and thereby permits loose mapping between logical resource data and physical memory. This allows the creation of large logical resources that utilize small amounts of physical memory. This is useful (for example) with terrain in games, and app UI.