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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Exist50

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Tough crowd here. The best gaming CPU is "disappointing".
I think, as usual, people got over-inflated expectations from wild rumors. Remember when 3D V-Cache was supposed to make it 37% faster, with the frequency penalty solved and even better scaling than Zen 3? #11,092

You can find comments from literally yesterday along the same vein. No surprise there's some whiplash once reality sets in.
 
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PJVol

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Tough crowd here. The best gaming CPU is "disappointing".
1. Let's see the benches first (rdna3 slides didn't add much trust to today's nice pictures)
2. I don't give a damn **** which CPU is best for gaming or how much it will cost and whatever.
The only thing I interested in is technology challenges and how good are engineers at solving them. So, yes... a tough crowd here in a TECH forum from the average consumer point of view.

Remember when 3D V-Cache was supposed to make it 37% faster, with the frequency penalty solved
Aside from an obvious 37% exaggeration, maybe you've got some insider info pointing to unreasonable expectations of “frequency penalty” improvement?
 
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Hail The Brain Slug

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Oct 10, 2005
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You clearly don't want to have an actual discussion, but I made four predictions across two posts.
  1. The 7800X3D and 7950X3D will be roughly equal in gaming.
  2. The 7800 X3D and 7950X3D will average 10-15% faster than the 13900K, again in gaming. And obviously when not GPU bound.
  3. The 13900KS will be 5-10% faster than the K.
  4. The KS may trade blows with the X3D when "when cranked up to 11 with fast RAM".
The third I agree will be closer to the 5%. The fourth, I thought it was clear I meant at 720P in certain games, with DDR5-8000 and TDP be damned.

I very well may have worded my posts initial poorly, but you're the one continuing to harp on the latter-half of that one post as if it was gospel.

So again, good day. This was a fun way to occupy the waste of time that was my Zoom meeting.

Alright, I see how I misread what you had written in that post to think you were indicating that "both" meant Zen4 3D + 13900k, instead of the 7800X3D and 7950X3D that you indicated. My apologies.
 
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Hans Gruber

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So what you guys are saying. They didn't fix the 3d v-cache temperature limit with the Zen 4 3D version. So clock speeds will be 400-500mhz lower than standard 7700x/7800x CPU's?
 

Hail The Brain Slug

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So what you guys are saying. They didn't fix the 3d v-cache temperature limit with the Zen 4 3D version. So clock speeds will be 400-500mhz lower than standard 7700x/7800x CPU's?

Unsure if it's thermals, voltage, or a combination of both. I mentioned a few posts ago I heard the Zen 4 3D CCD is limited to 1.4V, which is higher than Zen 3D 1.35 VMax. There were rumors they refined the entire setup to improve thermals, which will be tested when we see reviews and samples in the wild. The fact they are willing to allow PBO and CO is a promising sign, as is the increased voltage. I think it seems like it's been meaningfully improved over Zen 3D, albeit not fully "fixed", as in made equivalent to a non-stacked die. I don't know if stacking can ever be made fully equivalent to a non stacked die for thermals and voltage tolerance, though.
 
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Hail The Brain Slug

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Why, because your favorite CPU isn't winning ? Without all the cache, the 7950x is a monster at multi-threaded apps, but at single threaded apps fell behind once in a while. This fixes that.

I think we all got used to AMD demonstrating a reasonably accurate suite of performance benchmarks, which frequently included ties or losses, until the RDNA3 announcement where it appears the vast majority of what they demonstrated was false.

I can understand the breach of trust at their last announcement might make some people more skeptical of their claims for the near future. That is, unless they can build that trust again.
 
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Harry_Wild

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Realistically, the "120%" of PC users are actually waiting for even cheaper AM5 motherboards. :grinning:

Current situation, $160 is too much for the cheapest AM5 board if you want to build a "cheap but very good PC".So another month of waiting, and only then it will be much easier when you have AM5 motherboards for $80-100$.
Maybe true but then one who have to wait still again for it to back in stock and plentiful to buy! Maybe another 6 months of waiting it out? I just buy what is available that a brand new chipset at any price for my 7600 that can do 24 lanes and DDR5 RAM at 6600! Remember, am planning to keep the motherboard to 2025+, that alone is worth to me, $300 for a decent motherboard!
 

Carfax83

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I'm curious about the performance of Zen 4 3D in games that use ray tracing. Raptor Lake has a huge performance lead over Zen 4 in heavy RT games like Spider-Man Miles Morales that use the CPU for BVH building and maintenance. Tests have it at nearly 50%.

The 3D cache should make a nice dent in that gap, but I doubt it will be enough to fully close it.
 

Kaluan

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Jan 4, 2022
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CapframeX being a Biased Intel fan yet again..
View attachment 74019
View attachment 74021
Ah, where's that (Intel branded) copium huffing device meme when you need it... :grin:


AMD Zen4X3D is "only this" and "only that"... my boy knows 13900K is "only" 6-7% faster than 5800X3D at 1080p, right? While also consuming more than twice the wattage in those gaming tasks... But eh, efficiency doesn't matter unless the brand you hate is bad at it right? :p (pretty sure I'll find him blasting RDNA3 power efficiency in his tweeter feed)

Going by AMD's numbers, which they didn't mislead with back in the 5000X3D drum-up period (and I hope they don't do now), 7800X3D is ~21% faster (8 game average) than 5800X3D and 7950X3D is ~16% faster (6 game average) than 13900K. That fits pretty great into the "5800X3D 6% slower than 13900K, 7000X3D 16% faster than 13900K... so ~21% faster than 5000X3D" triangle.
(If we asume 7800, 7900 and 7950 X3Ds all perform roughly the same in games)
 

Hail The Brain Slug

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Ah, where's that (Intel branded) copium huffing device meme when you need it... :grin:


AMD Zen4X3D is "only this" and "only that"... my boy knows 13900K is "only" 6-7% faster than 5800X3D at 1080p, right?

Going by AMD's numbers, which they didn't mislead with back in the 5000X3D drum-up period (and I hope they don't do now), 7800X3D is ~21% faster (8 game average) than 5800X3D and 7950X3D is ~16% faster (6 game average) than 13900K. That fits pretty great into the "5800X3D 6% slower than 13900K, 7000X3D 16% faster than 13900K... so ~21% faster than 5000X3D" triangle.
(If we asume 7800, 7900 and 7950 X3Ds all perform roughly the same in games)

It will be interesting to see if the dual CCD Zen 4 3D scheduling will "solve" the cross-CCD penalty that the 7900X and 7950X currently see in some games against the 7700X. If it does, and it makes 3D cache favored games run entirely on the 3D CCD, it should perform practically the same I'd think. Problem is if some games that don't favor the cache end up cross-CCD or not. They do now, and that seems like something AMD could have or might work on in the future.
 
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Hans Gruber

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Dec 23, 2006
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I think it would make sense for AMD to roll back the TDP for the 3D-vache to the Zen 3 levels (105w). If the non X processors can push 5.2-5.3ghz with reduced TDP numbers. It would make sense for AMD to roll back the TDP to make the power/performance ratio much better.

AMD had a good thing going with Zen2 and Zen3. Why did they decide to screw up their huge power consumption advantage with Zen4?
 
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Kaluan

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It will be interesting to see if the dual CCD Zen 4 3D scheduling will "solve" the cross-CCD penalty that the 7900X and 7950X currently see in some games against the 7700X. If it does, and it makes 3D cache favored games run entirely on the 3D CCD, it should perform practically the same I'd think. Problem is if some games that don't favor the cache end up cross-CCD or not. They do now, and that seems like something AMD could have or might work on in the future.
Here's something that might interest you (and everyone else interested in dual-CCD gaming):

Perhaps these W11 changes can exted to non-X3D dual-CCD Ryzen 7000 in some way?


Edit: And a bonus for me, seeing that troll get owned again. :grin:
 
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Joe NYC

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So what you guys are saying. They didn't fix the 3d v-cache temperature limit with the Zen 4 3D version. So clock speeds will be 400-500mhz lower than standard 7700x/7800x CPU's?

5800x3d issue was with voltage, not temperature, but these are somewhat related... Temperature is less of a problem than a hard voltage limit - for overclocking...
 
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Saylick

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CapframeX being a Biased Intel fan yet again..
View attachment 74019
View attachment 74021
Ugh, that guy spends more time posting bait tweets that are either pro-Intel or pro-Nvidia rather than tweets that promote his own software.

Also, I don't understand people's self-proclaimed responsibility for having to "keep AMD hype in check", especially when I don't really see the market as being heavily AMD favored to begin with, and not when AMD is still the underdog in terms of company size. I refuse to believe that a handful of Youtube leakers constitute the bastion of "over hyping" that he's trying to "correct".
 

Hail The Brain Slug

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Oct 10, 2005
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Here's something that might interest you (and everyone else interested in dual-CCD gaming):

Perhaps these W11 changes can exted to non-X3D dual-CCD Ryzen 7000 in some way?


Edit: And a bonus for me, seeing that troll get owned again. :grin:

.... Seems suspect because as far as I am aware from every source I've seen, 5800X3D VMax was 1.35V, not 1.1V. Kind of an odd fact to get wrong....?

I have seen the details about PBO+CO being available on Zen 4 3D, as well as the other details regarding scheduler management. My question was made knowing everything presented there.

Current behavior seems to be to favor CCD0, and if enough threads are requested (even if they do little work) it will begin to schedule them on CCD1. Just because they instruct the scheduler to favor the 3D Cache CCD doesn't mean it won't spill over additional threads.

Granted they seem to be putting forth game-specific and application-specific instructions for the scheduler, according to what I've seen, so perhaps they will also tackle this issue for both 3D and non 3D dual CCD chips.
 
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