About the ngg path.
From amd whitepaper
http://radeon.com/_downloads/vega-whitepaper-11.6.17.pdf
"This next-generation geometry (NGG) path is much more flexible and programmable than before. To highlight one of the innovations in the new geometry engine, primitive shaders are a key element in its ability to achieve much higher polygon throughput per transistor. Previous hardware mapped quite closely to the standard Direct3D rendering pipeline, with several stages including input assembly, vertex shading, hull shading, tessellation, domain shading, and geometry shading. Given the wide variety of rendering technologies now being implemented by developers, however, including all of these stages isn’t always the most ecient way of doing things. Each stage has various restrictions on inputs and outputs that may have been necessary for earlier GPU designs, but such restrictions aren’t always needed on today’s more flexible hardware.
“Vega’s” new primitive shader support allows some parts of the geometry processing pipeline to be combined and replaced with a new, highly ecient shader type. These flexible, general-purpose shaders can be launched very quickly, enabling more than four times the peak primitive cull rate per clock cycle. In a typical scene, around half of the geometry will be discarded through various techniques such as frustum culling, back-face culling, and small-primitive culling. The faster these primitives are discarded, the faster the GPU can start rendering the visible geometry. Furthermore, traditional geometry pipelines discard primitives after vertex processing is completed, which can waste computing resources and create bottlenecks when storing a large batch of unnecessary attributes. Primitive shaders enable early culling to save those resources."
Well they better get that to work !