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AMD Zen 3 ‘Ryzen 4000 And EPYC Milan’ CPU Rumors: Up To 15% IPC Increase, Larger L3 Cache Available Per CCX

Apr 7, 2020
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AMD's Zen 3 core architecture will soon be powering the next-generation Ryzen 4000 desktop and 3rd Gen EPYC lineup. While we have got little hints of what to expect from the upcoming processor architecture, it looks like Adored TV has received some extra information on what Zen3 would have to offer & what PC audiences can expect from AMD's upcoming CPU lineup.

AMD Zen 3 Based Ryzen 4000 And EPYC Milan CPU Rumors - 10-15% IPC Uplift, Increased Cache Per CCX

While we had previously learned that AMD's Zen 3 CPU architecture was going to be a significant uplift in terms of performance and efficiency, Adored TV is saying otherwise. The information he has posted out seems to indicate that Zen 3 would be an evolution over Zen 2 which would make the upcoming architecture a little less impressive than we previously thought so. With that said, let's take a look at the information.

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First of all, its mentioned that Zen 3 will include a single CCX consisting of 8 cores. So till now, Zen and Zen 2 had two core complexes on the same die with each CCX consisting of 4 cores. But with Zen 3, each CCX would hold 8 cores so that's essentially a single CCD. Diving further into the core structure of the Zen 3 CCD/CCX, since the CCD has moved to just one CCX, the entire L3 cache can now be shared across all 8 cores rather than each CCX consisting of two slices of L3 caches per CCX in the previous Zen cores. So we have 512 KB of L2 cache per core and 32 MB of L3 cache per CCX or CCD.

Zen 2 also featured 32 MB of L3 cache, but that was split between the two CCX's while Zen 3 will have the full 32 MB of L3 cache available on the same CCD. Another interesting thing pointed out is that 32 MB of L3 cache per CCX would be the absolute limit of what's possible on Zen 3 unlike what was previously suggested in a leaked presentation of Zen 3 which hinted at a possibility of more than 32 MB L3 cache.

Coming to the most interesting bit, it is mentioned that Zen 3 would feature an IPC uplift of 10-15% on a single thread. Interestingly, this is about the same IPC bump in Zen 2 which sounds great but is a little less than what we had initially hoped for or at least what AMD's Senior representatives had hinted in interviews. It is also stated that the 3rd Gen EPYC Milan A0 silicon is currently being tested. Simultaneous Multi-Threading is said to not work on A0 samples but B0 samples which are expected to come out by September would definitely improve upon the older silicon. So if we get to see some early sample benchmarks, then we should take this into account.

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In addition to Zen 3, Adored TV also mentions Zen 4 in his post and suggests a couple of new features to be expected on Ryzen 5000 and 4th Gen EPYC Genoa processors such as a new socket, 1 MB of L2 cache per core, support for AVX-512 instructions, further improvement in IPC and fabrication on the 5nm process node.

AMD CPU Roadmap (2018-2020)

Ryzen FamilyRyzen 1000 SeriesRyzen 2000 SeriesRyzen 3000 SeriesRyzen 4000 SeriesRyzen 5000 Series
ArchitectureZen (1)Zen (1) / Zen+Zen (2) / Zen+Zen (3) / Zen 2Zen (4) / Zen 3
Process Node14nm14nm / 12nm7nm7nm+5nm
High End Server (SP3)EPYC 'Naples'EPYC 'Naples'EPYC 'Rome'EPYC 'Milan'EPYC 'Genoa'
Max Server Cores / Threads32/6432/6464/128TBDTBD
High End Desktop (TR4)Ryzen Threadripper 1000 SeriesRyzen Threadripper 2000 SeriesRyzen Threadripper 3000 Series (Castle Peak)Ryzen Threadripper 4000 Series (Genesis Peak)Ryzen Threadripper 5000 Series
Max HEDT Cores / Threads16/3232/6464/12864/128?TBD
Mainstream Desktop (AM4)Ryzen 1000 Series (Summit Ridge)Ryzen 2000 Series (Pinnacle Ridge)Ryzen 3000 Series (Matisse)Ryzen 4000 Series (Vermeer)Ryzen 5000 Series
Max Mainstream Cores / Threads8/168/1616/32TBDTBD
Budget APU (AM4)N/ARyzen 2000 Series (Raven Ridge)Ryzen 3000 Series (Picasso Zen+)Ryzen 4000 Series (Renior Zen 2)Ryzen 5000 Series (Cezanne Zen 3)
Year20172018201920202021/2022?

Here's Everything We Know About The Zen 3 Based Ryzen 4000 'Vermeer' Desktop CPUs

The AMD Zen 3 architecture is said to be the greatest CPU design since the original Zen. It is a chip that has been completely revamped from the group up and focuses on three key features of which include significant IPC gains, faster clocks and higher efficiency.

AMD has so far confirmed themselves that Zen 3 brings a brand new CPU architecture, which helps deliver significant IPC gains, faster clocks and even higher core counts than before. Some rumors have even pointed to a 17% increase in IPC and a 50% increase in Zen 3's floating-point operations along with a major cache redesign.

When asked about what kind of performance gain Milan's CPU core microarchitecture, which is known as Zen 3, will deliver relative to the Zen 2 microarchitecture that Rome relies on in terms of instructions processed per CPU clock cycle (IPC), Norrod observed that -- unlike Zen 2, which was more of an evolution of the Zen microarchitecture that powers first-gen Epyc CPUs -- Zen 3 will be based on a completely new architecture.

Norrod did qualify his remarks by pointing out that Zen 2 delivered a bigger IPC gain than what's normal for an evolutionary upgrade -- AMD has said it's about 15% on average -- since it implemented some ideas that AMD originally had for Zen but had to leave on the cutting board. However, he also asserted that Zen 3 will deliver performance gains "right in line with what you would expect from an entirely new architecture."

- The Street

Other rumors have pointed out to a 50% increase in overall floating-point performance. We also got to see a major change to the cache design in an EPYC presentation, which showed that Zen 3 would be offering a unified cache design which should essentially double the cache that each Zen 3 core could have access compared to Zen 2.

The CPUs are also expected to get up to 200-300 MHz clock boost, which should bring Zen 3 based Ryzen processors close to the 9th Generation Intel Core offerings. That, along with the massive IPC increase and general changes to the architecture, would result in much faster performance than existing Ryzen 3000 processors, which already made a huge jump over Ryzen 2000 and Ryzen 1000 processors while being an evolutionary product rather than revolutionary, as AMD unveiled very recently.

The key thing to consider is that we will get to see return of the chiplet architecture and AMD will retain support on the existing AM4 socket. The AM4 socket was to last until 2020 so it is likely that the Zen 3 based Ryzen 4000 CPUs would be the last family to utilize the socket before AMD goes to AM5 which would be designed around future technologies such as DDR5 and PCIe 5.0. AMD's X670 chipset was also hinted as to arrive by the end of this year and will feature enhanced PCIe Gen 4.0 support and increased I/O in the form of more M.2, SATA, and USB 3.2 ports.

As for competition, the AMD Ryzen 4000 'Zen 3 Vermeer' lineup would compete against Intel's soon to be released Comet Lake-S and its upcoming Rocket Lake-S desktop processors. Tackling the Intel Comet Lake-S won't be so hard since the Ryzen 3000 CPUs are competitively positioned against the entire lineup as evident from the recent performance leaks, but Rocket Lake-S seems to be a major architectural uplift for Intel (although still based on 14nm process) which might just be Intel's way back in the desktop mainstream market.

With that said, Rocket Lake-S is still something that needs to be evaluated prior to its release before we can call it a Zen 3 challenger but time would make it clear. As for now, the competitive advantage that AMD has with its Zen 2 based Ryzen 3000 is just way too big compared to whatever Intel has in their sleeves for this year and Zen 3 based Ryzen 4000 processors are going to push that envelope even further.

AMD CPU Roadmap (2018-2020)

Ryzen FamilyRyzen 1000 SeriesRyzen 2000 SeriesRyzen 3000 SeriesRyzen 4000 SeriesRyzen 5000 Series
ArchitectureZen (1)Zen (1) / Zen+Zen (2) / Zen+Zen (3) / Zen 2Zen (4) / Zen 3
Process Node14nm14nm / 12nm7nm7nm+5nm
High End Server (SP3)EPYC 'Naples'EPYC 'Naples'EPYC 'Rome'EPYC 'Milan'EPYC 'Genoa'
Max Server Cores / Threads32/6432/6464/128TBDTBD
High End Desktop (TR4)Ryzen Threadripper 1000 SeriesRyzen Threadripper 2000 SeriesRyzen Threadripper 3000 Series (Castle Peak)Ryzen Threadripper 4000 Series (Genesis Peak)Ryzen Threadripper 5000 Series
Max HEDT Cores / Threads16/3232/6464/12864/128?TBD
Mainstream Desktop (AM4)Ryzen 1000 Series (Summit Ridge)Ryzen 2000 Series (Pinnacle Ridge)Ryzen 3000 Series (Matisse)Ryzen 4000 Series (Vermeer)Ryzen 5000 Series
Max Mainstream Cores / Threads8/168/1616/32TBDTBD
Budget APU (AM4)N/ARyzen 2000 Series (Raven Ridge)Ryzen 3000 Series (Picasso Zen+)Ryzen 4000 Series (Renior Zen 2)Ryzen 5000 Series (Cezanne Zen 3)
Year20172018201920202021/2022?
What do you want to see in AMD's next-gen desktop CPUs?
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