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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Saylick

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Has it been revealed if the V-Cache is on N6, as has been rumored? Or is it N5?
No confirmation that I've seen. Just guesses.

If I were a betting man, it's likely N6. SRAM doesn't scale with newer nodes, so why spend the money fabbing it on N5? Seeing as how the voltage characteristics of the V-cache modestly improved, that's likely just the uplift from N7 to N6.
 
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In2Photos

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Also may I just add, with all this negativity here, I don't think I've seen one(1) person comment (let alone positively) that we're getting 7000X3D in February, not the rumored March or later. That's a good thing? IDK I'm not sure anymore with all the gloom tinting. Everyone's too focused pointing and debating shortcomings, real or imagined or just minutiae.

Neither has there been much talk about expected pricing. I would be happy with $399 MSRP for the 7800X3D, slotting in above $349 quasi-MSRP 7700X and $329 MSRP (boxed w/ a cooler) 7700. But it's probably gonna be $449 or more.
I've been waiting a while to do a new build for myself so I'm happy with the February release. My guess is that it will be the end of February and not the beginning which would be very close to the original March rumor. I have a feeling $449 is pretty accurate but $399 or $429 are also possible.
 
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Kaluan

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This is the million dollar question. If the 7800 top boost is 400MHz lower than 7700 and is limited to 5GHz, will it clock to this value on all cores (like 7700x does i presume) or will it clock 300~400 MHz lower in that situation as well? Does 5800x3D clock lower in all core scenario compared to its limited single core boost?
5800X3D clocks to ~4,32GHz in all core loads (like rendering) and 4,45GHz in single core. So not a lot of difference. It also draws less power than 5800X under similar heavy loads.
All of this just points to me that it's possibly artificially limited.

Curve Optimizer or PBO may claw back some of that clockspeed or it may not do much. But it's certainly something we should hope reviewers dig into properly (SkatterBench where u at bro?).

Fmax is also a question, 7700X actually goes up to 5,55GHz on multiple cores in lightly threaded or light multithreaded loads. Real world clocks of stock 7800X3D may be different than advertised 5GHz as well.
 

biostud

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Also may I just add, with all this negativity here, I don't think I've seen one(1) person comment (let alone positively) that we're getting 7000X3D in February, not the rumored March or later. That's a good thing? IDK I'm not sure anymore with all the gloom tinting. Everyone's too focused pointing and debating shortcomings, real or imagined or just minutiae.

Neither has there been much talk about expected pricing. I would be happy with $399 MSRP for the 7800X3D, slotting in above $349 quasi-MSRP 7700X and $329 MSRP (boxed w/ a cooler) 7700. But it's probably gonna be $449 or more.
Could be February 28th, so.... :p
 

CP5670

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Jun 24, 2004
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I'm thinking of getting one of these and an X670E setup. The 7800X3D and 7900X3D have pretty different boost clocks, I wonder if it will be worth getting the higher model even if you don't need the cores.
 

biostud

Lifer
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I'm thinking of getting one of these and an X670E setup. The 7800X3D and 7900X3D have pretty different boost clocks, I wonder if it will be worth getting the higher model even if you don't need the cores.
Most believe the boost clocks only will be the CCD without cache, while the one with cache will probably top out at 5Ghz like the 7800X3D.
 
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Hitman928

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Yes,

View attachment 74088


The two IODs will likely look like a single one on package. That's a lot of routing to do.

How will they look like 1 IOD if they are separate dies? How would the data transfer between the groupings be handled? If this is user created, it should be made clear as such, rather than attempting to make it look like an AMD slide.
 
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moinmoin

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I seriously doubt that we are the first ones to realize that this may need some changes on the OS. Surely AMD realizes this which is why AMD said they have been working with Microsoft already.
That's the least we should expect. But AMD really ought to work on being able to offer required software and OS tweaks already at the time when their products launch. "Fine wine" makes for a nice meme but essentially expanding it across the product range (now potentially with "Ryzen AI" as well etc.) is not exactly a good look.
 
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Hail The Brain Slug

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Most believe the boost clocks only will be the CCD without cache, while the one with cache will probably top out at 5Ghz like the 7800X3D.

AFAIK all of this this was confirmed independently by multiple press members contacting AMD.

High boost on non cache CCD

5.0ghz/1.4v max on cache CCD

Albeit PBO and CO will be enabled this time around, so potentially able to get >5.0GHz on the cache CCD granted thermals and sample quality are good
 
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In2Photos

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That's the least we should expect. But AMD really ought to work on being able to offer required software and OS tweaks already at the time when their products launch. "Fine wine" makes for a nice meme but essentially expanding it across the product range (now potentially with "Ryzen AI" as well etc.) is not exactly a good look.
Did I miss the part where AMD said the chips wouldn't work as intended when they launch? Or that special software will need to be developed and it isn't ready yet? Do you have insider information that these tools don't already exist?
 

Hail The Brain Slug

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Did I miss the part where AMD said the chips wouldn't work as intended when they launch? Or that special software will need to be developed and it isn't ready yet? Do you have insider information that these tools don't already exist?

We can only assume they intend to have the scheduler driver prepared for launch. Given the magnitude of the performance deficit in gaming if it was not, it would be a PR disaster.
 

Saylick

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N5/N4 still have ok SRAM scaling vs N7/N6, so in theory, there's still an advantage to be had. Since it's the same capacity, someone could probably do some quick estimates from screenshots.
Sorry, what I meant was that it doesn't scale relative to the cost. You might get 1.3x SRAM scaling going to N5/N4, but the node costs far more than 1.3x. Additionally, I presume the same V-cache chiplets go into Genoa-X, which doesn't clock nearly as high so the clock benefits of a V-cache die on N5/N4 would be unnecessary.
 

CP5670

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Most believe the boost clocks only will be the CCD without cache, while the one with cache will probably top out at 5Ghz like the 7800X3D.

That's interesting, then it may be better to get the 7800X3D, but clocks that much higher would actually help in old games that are bottlenecked by a single thread.

It also seems the B650E boards are nearly identical to the X670E ones but quite a bit cheaper, so I might go for one of them.
 

Thunder 57

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Except it's not just with that particular game or that particular engine. Nice try though.

All I could find on Spiderman was a reddit post linking a Computerbase.de benchmark. If it was such a big deal there would be far more mention of it.

Not just that game or engine? List another. You didn't because any evidence must be so shallow it's probably idiots on some forum who don't know what they are doing. If RT was broken on AMD CPU's in multiple games, it would be huge news. Why not move on and try to find another reason Zen sucks?
 

Exist50

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Sorry, what I meant was that it doesn't scale relative to the cost. You might get 1.3x SRAM scaling going to N5/N4, but the node costs far more than 1.3x. Additionally, I presume the same V-cache chiplets go into Genoa-X, which doesn't clock nearly as high so the clock benefits of a V-cache die on N5/N4 would be unnecessary.
Ah, gotcha.

On the topic, I wonder what the actual source of the frequency deficit is. Thermals, hybrid bond latency/overhead, extra latency from capacity, etc. Would be interesting if nothing else.
 

Carfax83

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All I could find on Spiderman was a reddit post linking a Computerbase.de benchmark. If it was such a big deal there would be far more mention of it.

Not just that game or engine? List another. You didn't because any evidence must be so shallow it's probably idiots on some forum who don't know what they are doing. If RT was broken on AMD CPU's in multiple games, it would be huge news. Why not move on and try to find another reason Zen sucks?

You're fairly intellectually lazy I see, always wanting others to find evidence for you when you're quite capable of doing it yourself....or maybe not. Computerbase.de is one of the best known and most credible German hardware review sites and they've done more testing with RT workloads than any other.

Core i9-13900K, i7-13700K & i5-13600K: Gaming Kings Review: Benchmarks in Games - ComputerBase

They tested Cyberpunk with RT, Far Cry 6 with RT, and Spider-Man PC Remastered with RT on an RTX 3090 Ti at 720p and the 13900K was nearly 30% faster than the 7950x in CBP and Spider-Man, and 17% faster with Far Cry 6. And let me remind you, this is with an RTX 3090 Ti. The gap would have been even wider if they had used an RTX 4090 for their first review.

Another reputable German review site, PCgameshardware.de, tested Spider-Man Miles Morales, which uses the same engine as Spider-Man Remastered but also includes RT shadows as well as reflections and found a nearly 50% gap between the 7950x and the 13900K.

Spider-Man: Miles Morales - CPU-Benchmarks (pcgameshardware.de)

Different games, different engines, different publishers. I'm sure you will find some way of accusing them of being biased towards AMD though LOL!

Witcher 3 with RT effects also shows large gaps and favors Raptor Lake. Unfortunately, GameGPU doesn't have access to Zen 4 CPUs, but they tested a 5900X and the 13900K was 62.5% faster. Zen 4 would likely have reduced the gap somewhat.

The Witcher 3: Wild Hunt v. 4.0 GPU/CPU test | Action / FPS / TPS | GPU test (gamegpu.com)

There are also other examples on YouTube I can post if requested. Fact is, this is a real weakness in Zen CPUs compared to Golden/Raptor Cove. It has to do with the CPU having to initialize and maintain BVH structures, which is very demanding on the CPU. I think ADL and RPL's strength in these workloads comes from having higher memory and cache bandwidth plus a wider core with more OoO resources and throughput.

RT BVH workloads are going to increase in the future as RT becomes more prevalent, so CPUs will need to be ready.

I'm sure you'll dismiss all of this though. Gotta keep the AMD hype train moving at all costs, no dissent allowed! :D
 

Hitman928

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There are also other examples on YouTube I can post if requested. Fact is, this is a real weakness in Zen CPUs compared to Golden/Raptor Cove. It has to do with the CPU having to initialize and maintain BVH structures, which is very demanding on the CPU. I think ADL and RPL's strength in these workloads comes from having higher memory and cache bandwidth plus a wider core with more OoO resources and throughput.

RT BVH workloads are going to increase in the future as RT becomes more prevalent, so CPUs will need to be ready.

How do you explain this then?

A188A39D-A678-4915-953D-4C094B6612DE.png

 

Carfax83

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How do you explain this then?

I don't know. The performance gap isn't very large to begin with, nothing like what I listed in my post. The 13900K also had the same average and 1% lows at 1080p and 1440p, which is odd because the game is mostly very GPU intensive.

I have the game so I know. The Spider-Man games are way more CPU intensive, and so is Cyberpunk 2077. A good example of how CPU intensive CBP 2077 can be, this guy tested a 5800X3D in the market place at 1080p DLSS quality with RT ultra on an RTX 4080 and maxed crowd settings and he couldn't maintain 60 FPS. If you look at the GPU load, it's low so it's being CPU bottlenecked.


Now here's a 13900K rig with an RTX 4090. The 4090 is being CPU bottlenecked because he's testing 1080p with DLSS set to quality and psycho RT settings and the GPU usage is also low. But look at the framerate. He stays in the triple digit territory practically the entire time.

 
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