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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Kjella - Thursday, June 13, 2019 - linkThe Ryzen 1800x got dropped $150 in MSRP nine months after launch, I think AMD thought octo-core might be a niche market they needed strong margins on but realized they'd make more money making it a mainstream part. I bought one at launch price and knew it probably wouldn't be great value but it was like good enough, let's support AMD by splurging on the top model. Very happy it's now paying off, even though I'm not in the market for a replacement yet.
deltaFx2 - Tuesday, June 11, 2019 - link@jjj: Rriigght... Moore's law applies to transistors. You are getting more transistors per sq. mm, and that translates to more cores. ST performance is an arbitrary metric you came up with. It's like expecting car power output (HP/W) go increase linearly every new model and it does not work that way. Physics. So, they innovate on other things like fuel economy, better drive quality, handling, safety features... it's life. We aren't in the 1980s anymore where you got 2x ST perf from a process shrink. Frequency scaling is long dead.
The other thing you miss is that the economies of scale you talk about are dying. 7nm is *more* expensive per transistor than 28nm. Finfet, quad patterning, etc etc. So "TSMC gives them more perf per dollar" compared to what? 28nm? No way. 14nm? Nope.
RedGreenBlue - Tuesday, June 11, 2019 - linkMulti-threaded performance does have an effect on single threaded performance in a lot of use cases. If you can afford a 12 core cpu instead of an 8, you would end up with better performance in the following situation: You have one or two multithreaded workloads that will have the most throughput when maxing out 7 strong threads, you want to play a game or run one task that is single-threaded. That single-threaded task is now hindered by the OS and any random updates or processes running in the background.
Point being, if you ever do something that maxes out (t - 1) cores, even if there's only one thread running on each, then suddenly your single threaded performance can suffer at the expense of a random OS or background process. So being able to afford more cores will improve single-thread performance in a multitasking environment, and yes multitasking like that is a reality today in the target market AMD is after. So get over it, because that's what a lot of people need. Nobody cares about you, it's the target market AMD and Intel care about.
FunBunny2 - Wednesday, June 12, 2019 - link"You have one or two multithreaded workloads that will have the most throughput when maxing out 7 strong threads, you want to play a game or run one task that is single-threaded."
the problem, as stated for years: 'they ain't all that many embarrassingly parallel user space problems'. IOW, unless you've got an app *expressly* compiled for parallel execution, you get nothing from multi-core/thread. what you do get is the ability to run multiple, independent programs. since we only have one set of hands and one set of eyes, humans don't integrate very well with OS/MFT. that's from the late 360 machines.
yankeeDDL - Thursday, June 13, 2019 - linkI am doing office work, and, according to Task Manager, there are ~3500 threads running on my laptop. Obviously, most threads are dormant, however, as soon as I start downloading something, while listening to music and editing an image, while the email client checks the email and the antivirus scans "everything", I will certainly have more than "10" threads active and running. Having more cores is nearly always beneficial, even for office use. I do swap often between a Core i7 5500 (2 cores, 4 threads) and a desktop with Ryzen 5 1600 (6C, 12T). It is an apples to oranges comparison, granted, but the smoothness of the desktop does not compare. The laptop chokes easily when it is downloading updates, the antivirus is scanning and I'm swapping between multiple applications (and it has 16GB of RAM - it was high end, 4 years back).
2C4T is just not enough in a productivity environment, today. 4C8T is the baseline, but anyone looking to future-proof its purchase should aim for 6C12T or more. Intel's 9 gen is quite limited in that respect.
Ratman6161 - Friday, June 14, 2019 - linkPersonally I would ignore anything to do with pricing at this point. The MSRP can be anything they want, but the street prices on AMD processors have traditionally been much lower. At ouor local Microcenter for example, 2700X can be had for $250 while the 2700 is only $180. On the new processors, if history is any indicator, prices will fall rapidly after release.
mode_13h - Tuesday, June 11, 2019 - linkI think the launch prices won't hold, if that's your main gripe.
I would like to be able to buy an 8-core that turbos as well as the 16-core, however. I hope they offer such a model, as their yields improve. I don't need 16 cores, but I do care about single-thread perf.
azazel1024 - Tuesday, June 11, 2019 - linkI have a financial drain right now, but once that gets resolved in (hopefully) a couple of months I think I am finally going to upgrade my desktop with Zen 2. Probably look at one of the 8-core variants. I am running an i5-3570 driven at 4Ghz right now.
So the performance improvement should be pretty darned substantial. And I DO a lot of multithread heavy applications like Handbrake, Photoshop, lightroom and a couple of others. The last time I upgraded was from a Core 2 Duo E6750 to my current Ivy Bridge. That was around a 4 year upgrade (I got a Conroe after they were deprecated, but before official EOL and manufacturing ceasing) IIRC. Now we are talking something like 6-7 years from when I got my Ivy Bridge to a Zen 2 if I finally jump on one.
E6750 to i5-3570 represented about a 4x increase in performance multithreaded in 4 years (or ballpark). i5-3570 to 3800x would likely represent about a 3x improvement in multithreaded in 6-7 years.
I wonder if I can swing a 3900x when the time comes. That would be probably somewhat over 4x performance improvement (and knowing how cheap I am, probably get a 3700x).
Peter2k - Tuesday, June 11, 2019 - linkYeah, but you have to say something negative about everything
bobhumplick - Tuesday, June 11, 2019 - linki agree. i mean its an incredible cpu line. but just throwing all of that extra die space and power budget at just more cores and cahce. i mean look at the cache to core ratio. when cpu makers just throw more cache or cores at a node shrink it can be because that makes the most sense at the time(the market, workloads, or supporting tech like dram have to catch up to enaable more per core performance) but it can also mean they just didnt know what else to do with the space.
maybe its just not possible to go much beyond the widths modern cpus are approaching. even intel is using a lot of space up for avx 512 which is similar to just adding more cores (more fpu crunchers ) so its possible that neither company knows how to balance all those intructions in flight or make use of more execution resources. maybe cores cant get much more performance.
but if so that means a prettyy boring future. especially if programmers cant find ways to use those cores in more common tasks