Discussion Speculation: Zen 4 (EPYC 4 "Genoa", Ryzen 7000, etc.)

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Vattila

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Except for the details about the improvements in the microarchitecture, we now know pretty well what to expect with Zen 3.

The leaked presentation by AMD Senior Manager Martin Hilgeman shows that EPYC 3 "Milan" will, as promised and expected, reuse the current platform (SP3), and the system architecture and packaging looks to be the same, with the same 9-die chiplet design and the same maximum core and thread-count (no SMT-4, contrary to rumour). The biggest change revealed so far is the enlargement of the compute complex from 4 cores to 8 cores, all sharing a larger L3 cache ("32+ MB", likely to double to 64 MB, I think).

Hilgeman's slides did also show that EPYC 4 "Genoa" is in the definition phase (or was at the time of the presentation in September, at least), and will come with a new platform (SP5), with new memory support (likely DDR5).

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What else do you think we will see with Zen 4? PCI-Express 5 support? Increased core-count? 4-way SMT? New packaging (interposer, 2.5D, 3D)? Integrated memory on package (HBM)?

Vote in the poll and share your thoughts! :)
 
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DisEnchantment

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With the current progression being:
Ryzen 2 channel
Thread ripper 4 channel
Epyc 8 channel

Is it not unreasonable to expect that, if the speculation about the new memory channel counts is correct, that next progression will be
Ryzen 3 channels
Thread ripper 6 channels
Epyc twelve channels

Low cost boards could have three slots.
DDR5 have two channels in one single DIMM. You can do 2 or 4 channels with 2 DIMMs.
Also DDR5 will bring higher capcacity modules and the PMIC is inside the DIMM.
PMIC cost moved from board to DIMM.
 
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LightningZ71

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DDR5 have two channels in one single DIMM. You can do 2 or 4 channels with 2 DIMMs.
Also DDR5 will bring higher capcacity modules and the PMIC is inside the DIMM.
PMIC cost moved from board to DIMM.

Ugh, yes, DDR5 is two "subchannels" per memory channel. I've made a point to indicate that in my posts over the last year, lest someone come along and get pedantic and correct me for not including it. I choose this time to not do that.... and it happens.

I was indicating DIMM channels, not individual memory channels. Currently, Ryzen desktop is two DIMM channels, with up to two DPC. My proposal is that desktop Ryzen will be moving to three DIMM channels, with up to two DPC. Low end or compact boards can have three DIMM slots. Higher end boards can have six.
 
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IEC

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I wouldn't mind having more memory bandwidth. It's seems unlikely that vendors would deal with the complexity of three channels of memory for the sake of bandwidth when the move from DDR4 to DDR5 would already provide improved bandwidth...

I'll be happy to be surprised, though my wallet wouldn't be!
 

DisEnchantment

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Don't think it works that way. It's still considered one channel but you get two half sized widths instead.
How does it work then? I am curious because I have not gone through the JEDEC spec, but AT overview
and from Rambus writeup, and this what I can surmise

1614690241823.png
Channel A and B can receive independent Command and addresses from the MC. Also dedicated Data Buffers for channel A and channel B
Channel A can perform operations while Channel B is in recovery.
This gives a smart MC to optimize addressing so that the queued memory request at the MC can be handled in parallel and not spending time to recover if it were a single channel.
 

uzzi38

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Oct 16, 2019
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If these rumors are accurate, I suspect we will see a 24 core desktop (AM5) part.
Hmm, I'm not so sure. Genoa seems to keep the same balance of memory channels to cores as Genoa, I'd be surprised if AMD do the opposite for desktops.

I could be totally wrong, but it doesn't make a great deal of sense to me personally.
 

Kedas

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Why is it called AVX3-512 and not AVX-512 like everyone is used to (nobody says AVX3), is it possible a small change compared to AVX-512?
 

eek2121

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Not when it's way more profitable to make 24 core EPYC and Threadripper CPUs. 16 is good for now, unless Intel gets to a point where they want to play 'core wars' with AMD, but I really doubt that will happen anytime soon.

Alder Lake will bump up core counts, I suspect AMD will respond in kind. TR has also been pushed up into workstation territory, so enthusiasts will likely want a replacement.
 

inf64

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I think AMD will go with 24C/48T Zen4 desktop parts on AM5, it's inevitable. I also think that Zen4 will have a decent IPC lead over Golden Cove and couple that with the fact that AlderLake is a hybrid of 8 GC and 8 weaker-than-Skylake cores it will be a re-run of Zen3 Vs Comet Lake. Higher IPC, higher performance in ST, embarrassingly higher performance in MT and most likely somewhat better gaming performance (although the GPUs might be a bottleneck).
 

blckgrffn

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www.teamjuchems.com
I think AMD will go with 24C/48T Zen4 desktop parts on AM5, it's inevitable. I also think that Zen4 will have a decent IPC lead over Golden Cove and couple that with the fact that AlderLake is a hybrid of 8 GC and 8 weaker-than-Skylake cores it will be a re-run of Zen3 Vs Comet Lake. Higher IPC, higher performance in ST, embarrassingly higher performance in MT and most likely somewhat better gaming performance (although the GPUs might be a bottleneck).

Yeah, it will be hard to show off that new Zen 4 gaming performance when you are stuck buying a new 1660Ti. /s (maybe)

I still thought DDR5 was going to be a big deal for IGPs - and yeah, I know DDR4 goes to the moon with aftermarket kit and LPDRR4x but most OEMs are probably sticking 2666 at best in most things. I don't know what the "least common denominator" speed of DDR5 will be but hopefully it is well north of that.

But I specifically thought that it was speed + somehow a wider channel that was going to create more breathing room for APU. I guess it is only the speed? Bummer.
 

uzzi38

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Yeah, it will be hard to show off that new Zen 4 gaming performance when you are stuck buying a new 1660Ti. /s (maybe)

I still thought DDR5 was going to be a big deal for IGPs - and yeah, I know DDR4 goes to the moon with aftermarket kit and LPDRR4x but most OEMs are probably sticking 2666 at best in most things. I don't know what the "least common denominator" speed of DDR5 will be but hopefully it is well north of that.

But I specifically thought that it was speed + somehow a wider channel that was going to create more breathing room for APU. I guess it is only the speed? Bummer.
The combination of RDNA2 + DDR5 (i.e. Rembrandt) is going to be massive for iGPUs, but that's best talked about in an actual RDNA2 thread :p
 

andermans

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I think AMD will go with 24C/48T Zen4 desktop parts on AM5, it's inevitable. I also think that Zen4 will have a decent IPC lead over Golden Cove and couple that with the fact that AlderLake is a hybrid of 8 GC and 8 weaker-than-Skylake cores it will be a re-run of Zen3 Vs Comet Lake. Higher IPC, higher performance in ST, embarrassingly higher performance in MT and most likely somewhat better gaming performance (although the GPUs might be a bottleneck).

I wonder if the primary competitor for zen4 on desktop/mobile won't be Golden Cove/Alder Lake but Meteor Lake. AFAIU there is nothing more precise about Zen4 launch dates than somewhere in 2022 and if it follows the pattern Zen4 mobile will likely be another CES launch at the start of 2023. e.g. if zen3+ is following a timeline closer to zen+ then zen4 could very well be a late fall 2022 release.

So it wouldn't be unthinkable that Zen4 mobile would release at roughly the same time as Meteor Lake mobile and desktop might not be that far off.
 
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Tarkin77

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Mark Papermaster at the Morgan Stanley Technology, Media and Telecom Conference yesterday said, next Generation Epyc (Genoa) coming in 2022 (leveraging 5nm) and Zen 5 is on track. Interestingly, he also mentioned 6nm.

My guess is Zen 3+ (6nm?) desktop Q3 2021, mobile Jan 2022, Zen 4 desktop end of March or in April 2022, Genoa in Q3 and mobile Zen 4 5nm again Jan (2023).
 

Tarkin77

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I wonder if the primary competitor for zen4 on desktop/mobile won't be Golden Cove/Alder Lake but Meteor Lake. AFAIU there is nothing more precise about Zen4 launch dates than somewhere in 2022 and if it follows the pattern Zen4 mobile will likely be another CES launch at the start of 2023. e.g. if zen3+ is following a timeline closer to zen+ then zen4 could very well be a late fall 2022 release.

So it wouldn't be unthinkable that Zen4 mobile would release at roughly the same time as Meteor Lake mobile and desktop might not be that far off.

Meteor Lake is intels 7nm 2023 product, isn't it? (could very well be late 2023 depending on their 7nm timeline). Zen 4 is a H1 2022 product.
 
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uzzi38

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I wonder if the primary competitor for zen4 on desktop/mobile won't be Golden Cove/Alder Lake but Meteor Lake. AFAIU there is nothing more precise about Zen4 launch dates than somewhere in 2022 and if it follows the pattern Zen4 mobile will likely be another CES launch at the start of 2023. e.g. if zen3+ is following a timeline closer to zen+ then zen4 could very well be a late fall 2022 release.

So it wouldn't be unthinkable that Zen4 mobile would release at roughly the same time as Meteor Lake mobile and desktop might not be that far off.
It's a constant back and forth hopefully from here on out. At the end of last year, we had Zen 3 being the top dog for 1T perf. At the end of this year (hopefully) we should see Alder Lake retake that crown. In the second half of next year, hopefully we'll see Zen 4 retake that crown once more.

There's nothing wrong with a bit of back and forth in the market, is there? I quite like things looking the way they are.
 

DrMrLordX

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Nobody knows "which AVX-512" gets implemented by AMD.

I would suspect either the same feature set as Cooper Lake or Ice Lake-SP. Maybe Sapphire Rapids (assuming it's any different than Ice Lake-SP) but I wouldn't be 100% sure about that.

My guess is Zen 3+ (6nm?) desktop Q3 2021, mobile Jan 2022, Zen 4 desktop end of March or in April 2022, Genoa in Q3 and mobile Zen 4 5nm again Jan (2023).

That's really, REALLY late for Raphael.
 
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Tarkin77

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I would suspect either the same feature set as Cooper Lake or Ice Lake-SP. Maybe Sapphire Rapids (assuming it's any different than Ice Lake-SP) but I wouldn't be 100% sure about that.



That's really, REALLY late for Raphael.

I wouldn't be suprised if AMD gets Zen 4 out the door befor Intel manages to ship ADL in any meaningful volume.
 

Timorous

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It's a constant back and forth hopefully from here on out. At the end of last year, we had Zen 3 being the top dog for 1T perf. At the end of this year (hopefully) we should see Alder Lake retake that crown. In the second half of next year, hopefully we'll see Zen 4 retake that crown once more.

There's nothing wrong with a bit of back and forth in the market, is there? I quite like things looking the way they are.

I don't think Zen 4 will be 2H 2022. Based on the 15 month cadence Q1 2022 seems more likely.