AMD Zen 2 Microarchitecture Analysis: Ryzen 3000 and EPYC Romeby Dr. Ian Cutress on June 10, 2019 7:22 PM EST
- Posted in
- Infinity Fabric
- PCIe 4.0
- Zen 2
- Ryzen 3000
- Ryzen 3rd Gen
Editor's Note: With Zen 2 set to launch tomorrow (7/7), here's our architecture analysis from last month for some timely background information.
We have been teased with AMD’s next generation processor products for over a year. The new chiplet design has been heralded as a significant breakthrough in driving performance and scalability, especially as it becomes increasingly difficult to create large silicon with high frequencies on smaller and smaller process nodes. AMD is expected to deploy its chiplet paradigm across its processor line, through Ryzen and EPYC, with those chiplets each having eight next-generation Zen 2 cores. Today AMD went into more detail about the Zen 2 core, providing justification for the +15% clock-for-clock performance increase over the previous generation that the company presented at Computex last week.
AMD’s Zen 2 Product Portfolio
The current products that AMD has announced that have Zen 2 cores include the Ryzen 3rd Generation consumer CPUs, known as the Ryzen 3000 family, and AMD’s next generation enterprise EPYC processor, known as Rome. As of today, AMD has announced explicit details of six consumer Ryzen 3000 processors, including core counts, frequencies, memory support, and power. Details about the server processor, aside from some peak values, are expected in due course over the next few months.
|AMD 'Matisse' Ryzen 3000 Series CPUs|
|Ryzen 9||3950X||16C||32T||3.5||4.7||8 MB||64 MB||16+4+4||3200||105W||$749|
|Ryzen 9||3900X||12C||24T||3.8||4.6||6 MB||64 MB||16+4+4||3200||105W||$499|
|Ryzen 7||3800X||8C||16T||3.9||4.5||4 MB||32 MB||16+4+4||3200||105W||$399|
|Ryzen 7||3700X||8C||16T||3.6||4.4||4 MB||32 MB||16+4+4||3200||65W||$329|
|Ryzen 5||3600X||6C||12T||3.8||4.4||3 MB||32 MB||16+4+4||3200||95W||$249|
|Ryzen 5||3600||6C||12T||3.6||4.2||3 MB||32 MB||16+4+4||3200||65W||$199|
The Zen 2 design paradigm, compared to the first generation of Zen, has changed significantly. The new platform and core implementation is designed around small 8-core chiplets built on TSMC’s 7nm manufacturing process, and measure around 74-80 square millimeters. On these chiplets are two groups of four-cores arranged in a ‘core complex’, or CCX, which contains those four cores and a set of L3 cache – the L3 cache is doubled for Zen 2 over Zen 1.
Each full CPU, regardless of how many chiplets it has, is paired with a central IO die through Infinity Fabric links. The IO die acts as the central hub for all off-chip communications, as it houses all the PCIe lanes for the processor, as well as memory channels, and Infinity Fabric links to other chiplets or other CPUs. The IO die for the EPYC Rome processors is built on Global Foundries' 14nm process, however the consumer processor IO dies (which are smaller and contain fewer features) are built on the Global Foundries 12nm process.
The consumer processors, known as ‘Matisse’ or Ryzen 3rd Gen or Ryzen 3000-series, will be offered with up to two chiplets for sixteen cores. AMD is launching six versions of Matisse on July 7th, from six cores to sixteen cores. The six and eight-core processors have one chiplet, while above this the parts will have two chiplets, but in all cases the IO die is the same. This means that every Zen 2 based Ryzen 3000 processor will have access to 24 PCIe 4.0 lanes and dual channel memory. Based on the announcements today, the prices will range from $199 for the Ryzen 5 3600, up to $700+ for the sixteen core (we’re waiting on final confirmation of this price).
The EPYC Rome processors, built on these Zen 2 chiplets, will have up to eight of them, enabling a platform that can support up to 64 cores. As with the consumer processors, no chiplet can communicate directly with each other – each chiplet will only connect directly to the central IO die. That IO die houses links for eight memory channels, and up to 128 lanes of PCIe 4.0 connectivity.
Before diving into the new product line, it is worth recapping where we currently sit in AMD’s planned roadmap.
In previous roadmaps, showcasing AMD’s movement from Zen to Zen 2 and Zen 3, the company has explained that this multi-year structure will showcase Zen in 2017, Zen 2 in 2019, and Zen 3 by 2021. The cadence isn’t exactly a year, as it has depended on AMD’s design and manufacturing abilities, as well as agreements with its partners in the foundries and the current market forces.
AMD has stated that its plan for Zen 2 was to always launch on 7nm, which ended up being TSMC’s 7nm (Global Foundries wasn’t going to be ready in time for 7nm, and ultimately pulled the plug). The next generation Zen 3 is expected to align with an updated 7nm process, and at this point AMD has not made any comment about a potential ‘Zen 2+’ design in the works, although at this point we do not expect to see one.
Beyond Zen 3, AMD has already stated that Zen 4 and Zen 5 are currently in various levels of their respective design stages, although the company has not committed to particular time frames or process node technologies. AMD has stated in the past that the paradigms of these platforms and processor designs are being set 3-5 years in advance, and the company states it has to make big bets every generation to ensure it can remain competitive.
For a small insight into Zen 4, in an interview with Forrest Norrod, SVP of AMD’s Enterprise, Embedded, and Semi-Custom group, at Computex, he exclusively revealed to AnandTech the code name of AMD’s Zen 4 EPYC processor: Genoa.
|AMD EPYC CPU Codenames|
|1st||2017||Naples||32 x Zen 1|
|2nd||2019||Rome||64 x Zen 2|
|3rd||2020||Milan||? x Zen 3|
|4th||?||Genoa||? x Zen 4|
|5th||?||?||? x Zen 5|
Forrest explained that the Zen 5 code name follows a similar pattern, but would not comment on the time frame for the Zen 4 product. Given that the Zen 3 design is expected mid-2020, that would put a Zen 4 product for late 2021/early 2022, if AMD follows its cadence. How this will play into AMD’s consumer roadmap plans is unclear at this point, and will depend on how AMD approaches its chiplet paradigm and any future adjustments to its packaging technology in order to enable further performance improvements.
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scineram - Wednesday, June 12, 2019 - linkNo.
Xyler94 - Thursday, June 13, 2019 - linkYes
Xyler94 - Thursday, June 13, 2019 - linkIf he meant 2700x, of course. Darn misreading :P
nevcairiel - Monday, June 10, 2019 - linkA quick note. AVX2 is actually primarily Integer. AVX1 (or just AVX) is 256-bit floating point. The article often refers to "full AVX2 support", which isn't necessarily wrong, but Zen2 also adds full AVX support equally.
NikosD - Saturday, June 15, 2019 - linkAVX256 is both integer and floating point because it includes AVX2 FMA which doubles floating point capability compared to AVX1
NikosD - Saturday, June 15, 2019 - linkAVX256 was a typo, I meant AVX2 obviously.
eastcoast_pete - Monday, June 10, 2019 - linkThanks Ian? Two questions: what is the official memory bandwidth for the consumer chips? (Sounds like they remain dual channel) and: Any words on relative performance of AMD's AVX 2 implementation vs. Intel's AVX 512 with software that can use either?
emn13 - Tuesday, June 11, 2019 - linkAVX-512 is a really misleading name; the interesting... bits... aren't the 512-bit width, but the dramatically increased flexibility. All kinds of operations are now maskable and better reshufflable, and where specific sub-segements of the vector were used, they're now sometimes usable at 1bit granularity (whereas previously that was greater).
Assuming x86 sticks around for high-perf computing long enough for compilers to be able to automatically leverage it and then for most software to use it, AVX-512 is likely to be quite the game changer - but given intel's super-slow rollout so far, and AFAIK no AMD support... that's going to take a while.
Which is all a long-winded way to say that you might well expect AMDs AVX2 implementation to be not all that much slower than intel's 512 when executing code that's essentially AVX2-esque (because intel drops the frequency, so won't get the full factor 2 speedup), but AVX-512 has the potential to be *much* faster than that, because the win isn't actually in vector-width.
GreenReaper - Tuesday, June 11, 2019 - linkIntel's own product segmentation has caused it to lose its first-mover advantage here. System software aside, there's little point in most developers seeking to use instructions that most of their users will not have (and which they themselves may not have). By the time software does support it, AMD is likely to have it. And of course an increasing number of developers will be pouncing on Zen 2 thanks to fast, cheap cores that they can use to compile on...
HStewart - Tuesday, June 11, 2019 - linkIntel only had AVX 512 versions in Xeon and Xeon derive chips, but the with Ice Lake ( don't really count Canon Lake test run ) AVX 512 will hit main stream starting with in a month and 2020 should be fully roll out.
As for AMD AVX 2 is true 256 bit, the last I heard is that it actually like dual 128 bit unless they change it in Zen 2. I serious doubt AMD AVX 2 implement is going to any much different that Intel AVX 2 and AVX 512 is a total different beast.
It funny years ago we heard the same thing about 64 bit in x86 instructions, and now we here in 512 bit AVX.
As for as AMD support for AVX 512, that does not matter much since Intel is coming out with AVX 512 in full line over next year or so.
But keep in mind unlike normal x86 instruction, AVX is kind of specialize with vectorize processing, I know with Video processing like Power Director this was a deciding factor earlier for it.,