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

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Vattila

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Oct 22, 2004
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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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Saylick

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In all fairness he really can't say anything else. Though it probably would have been better to say nothing at all in that regard.
I agree. He could have left it at "Alderlake is a great success and we're back in the game". Everything on top of that was just his usual brand of overhype with the chance of underdelivering (*cough* SPR delays *cough*). Contrast that with Lisa Su's style of sandbagging and letting the products speak for themselves.
 

Markfw

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I agree. He could have left it at "Alderlake is a great success and we're back in the game". Everything on top of that was just his usual brand of overhype with the chance of underdelivering (*cough* SPR delays *cough*). Contrast that with Lisa Su's style of sandbagging and letting the products speak for themselves.
And the fact that the only things they are clearly in the lead, are gaming and a few single threaded apps, does not make them on top, just "in the game". Not to mention the ecores problems, and the power problem (mostly on the 12900k).

Edit: One thing it DOES say is that they know they were NOT in the lead until recently in the consumer market.
 

Saylick

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And the fact that the only things they are clearly in the lead, are gaming and a few single threaded apps, does not make them on top, just "in the game". Not to mention the ecores problems, and the power problem (mostly on the 12900k).

Edit: One thing it DOES say is that they know they were NOT in the lead until recently in the consumer market.
We'll see how the sales numbers look at the end of this quarter because November's sales numbers from Mindfactory didn't look so hot. Budget LGA1700 motherboards aren't fully launched, so if I were Pat, I'd reserve on saying that Alderlake puts me the lead until I knew that it was selling closer to 1:1 with Ryzen.
 
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CHADBOGA

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We'll see how the sales numbers look at the end of this quarter because November's sales numbers from Mindfactory didn't look so hot. Budget LGA1700 motherboards aren't fully launched, so if I were Pat, I'd reserve on saying that Alderlake puts me the lead until I knew that it was selling closer to 1:1 with Ryzen.
With Intel's imminent release of CPU's up and down the range, plus finally cheap motherboards, Intel looks poised to take a lot of desktop share away from AMD, whilst AMD is focusing on the server market.
 

Saylick

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With Intel's imminent release of CPU's up and down the range, plus finally cheap motherboards, Intel looks poised to take a lot of desktop share away from AMD, whilst AMD is focusing on the server market.
We shall see. I'm not convinced Intel will make enough of a dent in AMD's leads on the desktop side just yet. Zen 4 is right around the corner.
 

eek2121

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With Intel's imminent release of CPU's up and down the range, plus finally cheap motherboards, Intel looks poised to take a lot of desktop share away from AMD, whilst AMD is focusing on the server market.
Maybe on the budget side? That will hurt Intel more than anything. They aren't touching AMD on the performance/enthusiast side of things. AMD was smart by having 12-16 core SKUs.
And isn't Zen 4 going to be DDR 5 only?

Not completely confirmed. Zen 4 is rumored to support DDR4, but the platform is, as of right now, DDR5 only. None of this matters anyway, The DDR5 situation will hopefully look very different when Zen 4 launches, and knowing AMD, they'll work with partners to ensure DDR5 availability.
 

MadRat

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Probably less of an obstacle than it's being made out to be. DDR4 and DDR5 are similar except for where the controlling interfaces sits, right? So it would make sense the CPU relinquishes signal control in DDR5 and asserts it when present for DDR4. The real challenge would be if it could turn DDR4 signaling more like DDR5, with independent 40-bit memory channels when appropriate. That would probably not be possible as DDR5 provides double the clocks and has signal integrity tuning built-in whereas DDR4 does not.
 

CHADBOGA

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Maybe on the budget side? That will hurt Intel more than anything. They aren't touching AMD on the performance/enthusiast side of things. AMD was smart by having 12-16 core SKUs.
The only current AMD cpu that one could argue makes more sense than an Intel offering is the 5950x, if you are a serious productivity user.

Otherwise if you care about games, in addition to productivity, the 12700x and 12600x are better buys when the more mainstream motherboards are available, than anything AMD currently offers from the 5900 on down.
 

eek2121

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The only current AMD cpu that one could argue makes more sense than an Intel offering is the 5950x, if you are a serious productivity user.

Otherwise if you care about games, in addition to productivity, the 12700x and 12600x are better buys when the more mainstream motherboards are available, than anything AMD currently offers from the 5900 on down.

You are completely ignoring power consumption. Also the 5900X beats the 12900K in many benchmarks, including gaming (Civ 6, for example).

On a side note, does anyone know if any legit reviewers have tested AMD chips with PBO enabled and PPT set to 241W?
 

biostud

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Feb 27, 2003
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Why even test Zen 3 at 241W? The gains are already bad at less power and they won't get any better. Intel chips seem to scale a little better under that much power, but the efficiency still sees a massive drop off.
Exactly, but this might change with zen4 and the 170W TDP rumor for top tier. Which is still a lot lower than 241W.
 
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Markfw

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With Intel's imminent release of CPU's up and down the range, plus finally cheap motherboards, Intel looks poised to take a lot of desktop share away from AMD, whilst AMD is focusing on the server market.
Exactly, but this might change with zen4 and the 170W TDP rumor for top tier. Which is still a lot lower than 241W.
Which is probably also for 24 or 32 cores.
 

Saylick

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"around the corner" more like "in half a year or more". I bet everybody hopes availability of DDR5 is somewhat better until then. But yeah, interesting times.
You're right, "around the corner" is more like "in half a year or more", but it's not like the scenario where Alderlake systems are flying off the shelves is "around the corner" either. Z690 and DDR5 are expensive, B660 just barely launched, and I'm guessing the GPU shortage really puts a damper on people buying new CPUs because you're not going to have a compete rig without the GPU. The point is, I am not sure there's enough runway between now and when Zen 4 launches for Intel to make a big enough splash in the market. It's kind of like the situation AMD are in with Nvidia for so many years: by the time AMD caught up with Nvidia, Nvidia were almost ready to roll out their following generation of graphics cards to maintain the lead.
 
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DrMrLordX

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Why even test Zen 3 at 241W? The gains are already bad at less power and they won't get any better. Intel chips seem to scale a little better under that much power, but the efficiency still sees a massive drop off.

Pretty much. You can set a 5900X to effectively unlimited PBO and it won't boost that high except under sub-zero cooling. N7 just won't go there.
 

DisEnchantment

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Have they said anything about the new IO die? Triple channel memory seems an unlikely design choice.
If they just sliced the Genoa IOD into 4 quadrants it is possible, each quadrant of the Genoa IOD has 3 UMCs.

For instance, that was what they did with Vermeer IOD, it is a quadrant of the Milan IOD

1642534818512.png

In Milan
2x CCDs are connected to one switch attached to 2x UMCs, for closest hop. There is a repeaters from the switch to the next introducing additional hops.
This is how the SRAT table is being calculated

Genoa will have 3x CCDs connected to one switch attached to 3x UMCs.
But of course it is just a possibility, and they might not reuse a portion of the IOD from Genoa at all like they did with Milan/Rome.
It does not mean that they will use 3x UMCs but just that they are there for use if they so desire.

1642535232692.png
 

Saylick

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Have they said anything about the new IO die? Triple channel memory seems an unlikely design choice.
I think what he's saying is that AMD could simply design a new IO die with an extra memory channel that handles 3 CCD SKUs if they wanted to make 24 core desktop products in the future. For now, we'll just get 2 CCD, dual channel parts. Who knows if they'll go with triple CCD products but it won't be leaps and bounds more difficult if they wanted to.
 

LightningZ71

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I dare say that AMD isn't quite as constrained by available engineering resources (manpower and budget) to make it impossible for them to devote resources to making an optimized IOD for desktop that isn't just a quadrant of the EPYC IOD. Granted, I think it would be awesome to have a triple channel system for a 24 core Ryzen system, but, I think it highly unlikely. Though, come to think of it, with Threadripper being restricted to the 8 (maybe 12 for next edition)memory channel TR Pro/Workstation series, there's a veritable gulf between a dual channel desktop and a 8-12 channel WS/HEDT platform...