AMD EPYC Zen 3 Milan And Zen 4 Genoa CPU Roadmap
A look at the roadmap slide shows that AMD's Zen 3 Milan EPYC processors have already reached the tapeout stage, meaning the initial design is complete, and will go into production for a customer launch in 2020. It also appears AMD is targeting 2020 for the tapeout of its Zen 4 Genoa EPYC processors, followed by a launch in 2021, if all goes to plan.
The slide reiterates what we already know about the Zen 3 architecture, which is that it is based on an enhanced 7-nanometer node, dubbed 7nm+. It is the same underlying architecture that will be found in AMD's next-generation Ryzen 4000 series CPUs for desktop consumers.
AMD Zen 3 Milan EPYC Socket And Cache
Milan will retain socket compatibility with current SP3 platforms. What that essentially means is another round of DDR4 memory support and many of the same features, with the bulk of changes coming from the architectural enhancements—AMD is taking aim at more performance per watt, as would be expected with a new generation of processors.
While AMD did not share information about clockspeeds, it did discuss a chance to the cache makeup. Zen 3 will bring about a change compared to Zen 2—whereas Zen 2 features 16MB of L3 cache per core complex (CCX) within a core complex die (CCD), Zen 3 will have a shared cache design consisting of 32MB or more of L3 cache for each CCD.
This alteration means each core would share the whole lot of L3 cache, rather than have access to just a portion of the overall allotment. It will be interesting to see what effect this ends up having on performance.
What We Know About AMD's Zen 4 EPYC Genoa Processors
We will have our answers about Milan's performance soon enough. Looking further down the roadmap, however, Zen 4 will bring about some more changes to the EPYC ecosystem. To start with, Zen 4 EPYC Genoa processors will feature a new SP5 socket. That means Milan will be the end of the road for the current SP3 platform.
AMD also apparently indicated that Genoa will bring about new capabilities. What those are remains to be seen, but support for the PCI Express 5.0 specification is certainly on the table. PCIe 5.0 doubles the bandwidth of PCIe 4.0, which could pay dividends in the server sector.
Summed up, AMD has built up some momentum with its Zen architecture and appears to be in good shape going forward.