After releasing the Zen+ based mobile and desktop processor families, AMD will focus on getting the real successor to Zen out of the door. Zen 2 will be manufactured on a new 7nm process and will sport many more enhancements than just a process improvement. Normally, a process improvement delivers cost savings (more cpus can be produced on a single wafer) and higher frequencies (thermal issues are resolved). AMD mentioned in presentations, that Zen 2 “Improves on Zen in Multiple Dimensions”.
3D stacking
Speculation leads AMD Rumors to think that AMD plans to stack multiple cpu complexes (each being a multi core Zen cpu) in the 3d dimension. By stacking a cpu die on top of another, one needs less communications lines (making communication faster) and could potentially double the maximum core count for Zen 2 based processors.
Epyc first
Of all of AMD’s processor families, the Epyc range is most likely to receive the Zen 2 treatment first. Not only are AMD laptop and desktop processors just refreshed with Zen+ 12nm treatment, but also due to the fact that system integrators and manufacturers often need long testing and certification time before implementing new technology. This way, AMD can roll out the new 7nm technology in low volume production first, before extending the technology to the high volume mobile and desktop Ryzen processor families. AMD is expected to start the Zen 2 rollout in 2019.