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

[Vattila]

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).

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!

 

[Exist50]

I think all of this talk of execution resources, buffer sizes, etc etc is all rather superfluous. GLC/RPC use significantly more transistors than Zen 4 (with higher power to match) yet doesn't have anything significant (IPC, meaningful frequency gap) to show for it. I think it's thus fair to conclude that GLC is bloated. The fact that they seem to be more or less reusing it until '24 doesn't make it look any better today. The opposite, if anything.

 

[Hans Gruber]

Can we talk about the non "X" Zen 4 7900 processor that is rated at 65w? Normally those would be 105w vs. the Zen 3 5900x. It says that it tops out @ 5.4ghz. Is anybody else interested in this CPU?

 

[coercitiv]

I laughed a bit. AMD is on a roll:

Latest AMD AGESA Firmware Inadvertently Disables Cores On Some Ryzen 5 7600X CPUs

It would seem that the AGESA ComboAM5PI 1.0.0.4 firmware has difficulties distinguishing the single-CCD Ryzen 5 7600X samples from the dual-CCD ones. It's plausible that it doesn't correctly recognize the CCD and, as a result, disables one of the processor's cores. According to the chi11eddog, the firmware locks down Core0.

 

[Timorous]

There's no evidence for that particular change to Zen 4c.

It fits logically though.

current density of Zen 4 is 94M xtors / mm^2. At that density the Zen 4c CCD would be around 117mm^2 (based on 11B xtors which is 2x Zen4 with 2B removed because L3 cache is not doubled) which is just too big so density must be higher and not by a small amount either. Now you might argue it will be fewer transistors than that because clocks are going to be lower and it may be a bit lower but to hit 80mm^2 at 94M per mm^2 needs to CCD to be no more than 7.5B transistors. With 32MB cache that is just 5.5B transistors for 16c. It just does not look doable, at least not while still being called Zen4.

On Bergamo you may only have 8 CCDs to fit but you have twice the links because the IO die is connected to each CCX so rather than the 12 CCXs you have in Genoa you need links for 16 CCXs, more if there are 2 IO dies (which with Siena would make perfect sense, 1 for Siena for upto 64 cores and 2 for Bergamo for upto 128 cores) so they can talk to each other and act as 1.

What you get with APU transistor density is 11B fitting in 79mm^2 which seems far easier to fit for both Siena and Bergamo.

It also fits because the APU CCX has been designed, tested and is in production so re-using that block and just doubling them up gives you a huge head start in designing the Zen 4c CCD and is pretty standard for AMD to do given they like to use as much as possible as wide as possible.

 

[moinmoin]

I laughed a bit. AMD is on a roll:

Latest AMD AGESA Firmware Inadvertently Disables Cores On Some Ryzen 5 7600X CPUs

Something is seriously off at AMD right now. Did they hire too many too quickly?

 

[leoneazzurro]

Something is seriously off at AMD right now. Did they hire too many too quickly?

Probably, I was thinking the same. Even if people is experienced, it takes time to be trained in the specific job.

 

[nicalandia]

AMD 7000 Non-X Review by Anandtech is up..

The AMD Ryzen 9 7900, Ryzen 7 7700, and Ryzen 5 7600 Review: Zen 4 Efficiency at 65 Watts

www.anandtech.com

TechpowerUp 7600 Review
AMD Ryzen 5 7600 Review - Affordable Zen 4 for the Masses

AMD Ryzen 5 7600 Review - Affordable Zen 4 for the Masses

Ryzen 5 7600 is AMD's most-affordable Zen 4 processor. It retails for only $230 and even comes with a heatsink. The testing in our review confirms that the performance difference to the more-expensive 7600X is minimal, and gaming performance even beats the 5800X3D.

www.techpowerup.com

 

[nicalandia]

AMD 7700 vs Ryzen 7700X

Impressive Performance/Efficiency. The 7700 is within 2% performance of the 7700X

AMD Ryzen 7 7700 vs. AMD Ryzen 7 7700X Benchmarks - OpenBenchmarking.org

openbenchmarking.org

 

[nicalandia]

AMD 7900 vs 7900X vs 12900K vs 5950X

AMD Ryzen 9 7900 vs. AMD Ryzen 9 7900X vs. Intel Core i9-12900K vs. AMD Ryzen 9 5950X Benchmarks - OpenBenchmarking.org

openbenchmarking.org

This has got to be the Most Efficient x86 CPU. 65W TDP beating not so old 12900K and 5950X

 

[Asterox]

Approximate worst case scenario for a small stock Wraith Stealth CPU cooler, Cinebench R23. In gaming or mixed use, significantly lower temperatures and higher CPU All Core boost can be expected.



As expected, Wraith Prism RGB cpu cooler is very good for CPU-s with lower TDP.Again Cinebench R23, and what are the CPU temperatures in the classic CPU rendering test.

 

[gdansk]

I laughed a bit. AMD is on a roll:

Latest AMD AGESA Firmware Inadvertently Disables Cores On Some Ryzen 5 7600X CPUs

I guess that explains why the 1.0.0.4 beta BIOS disappeared for my X670 board.

 

[Harry_Wild]

 

[yuri69]

Something is seriously off at AMD right now. Did they hire too many too quickly?

Nah, it seems to be more or less in line with the previous releases.

Early Zen 1s were replaced due to an errata causing segfaults.
Zen 2 era got boosting issues resulting in the meme "ABBA" version.
Zen 3 era got those endless USB port issues.

RDNA1 got endless stream of those black-screen reports.
Early RDNA2 got problems with power management.
RDNA 3 is... RDNA3.

 

[eek2121]

AMD 7900 vs 7900X vs 12900K vs 5950X

View attachment 74280

AMD Ryzen 9 7900 vs. AMD Ryzen 9 7900X vs. Intel Core i9-12900K vs. AMD Ryzen 9 5950X Benchmarks - OpenBenchmarking.org

openbenchmarking.org

This has got to be the Most Efficient x86 CPU. 65W TDP beating not so old 12900K and 5950X

View attachment 74281

The 7950X is likely more efficient when run at lower power limits. I know it is a beast when TDP is set to 65W. AMD likely does not use the best dies with these non-X chips.

 

[Exist50]

Early Zen 1s were replaced due to an errata causing segfaults.

IIRC, that particular issue was that their hardware random number generator was stuck to all 0s, or something like that. Don't recall where I heard that, but it's kinda funny.

 

[BorisTheBlade82]

IIRC, that particular issue was that their hardware random number generator was stuck to all 0s, or something like that. Don't recall where I heard that, but it's kinda funny.

Well, it's not that funny when you need it for Crypto/ISEC 😉

 

[nicalandia]

I would be very surprised if AMD just used APU desing(half L3) to get the space required to put 128 Cores worth of die area on the same package as Genoa.

 

[itsmydamnation]

non X's look good, now all we need is some good prices for GPU's more lower tier MB options and it might be worth upgrading..........

 

[nicalandia]

non X's look good, now all we need is some good prices for GPU's more lower tier MB options and it might be worth upgrading..........

That 7600 is a perfect place holder for a future upgrade to a 7900X3D in 2024 for many people.

 

[lopri]

We have enough information already but let me add one more graph. Didn't Computerbase.de not too long ago publish a chart that showed 7700X, 7900X, and 7950X at same performance rating at 45W? I thought someone linked that chart here. This is a new chart apparently.

 

[Harry_Wild]

Max wattage!😁👍 Might get the 7900 instead of 7600!

 

[Vattila]

A while back in the thread, @Timmah! and I discussed the labelling design for the Ryzen processors (see post #7386).

Spoiler: My proposed design

Did AMD listen?



In the latest design, seen in 7950X3D, note that they have made the font for "RYZEN" taller (also, the stroke width is reduced and corrected, for a lighter look and a more balanced "Y" in particular, which looked somewhat puny and out-of-place before). For the full product name, they have condensed the font and made the word spacing wider. For the product details, they now use a nicer condensed font. They have dropped "DIFFUSED IN TAIWAN" altogether, for less clutter. And the whole thing is nicer aligned.

Edit: I think it looks pretty nice now, but I still would want to get rid of the repetition and make the model number larger instead. While they keep using the tier number in the product name, which I think is awful (AMD even gets it wrong in keynote presentations), they could make it more distinct, e.g. by putting it in reverse. Something like this:



Note that I have reduced the size of the AMD logo slightly, so that the AMD arrow now sits centred above the "Z" in "RYZEN", as well as centred on the chip overall. I think this looks nicer and more balanced. I have moved the out-of-place "D" (for "demo sample", I presume) behind the SKU number, as to be less disruptive. Also note that the tier number is fittingly aligned below the "Y" (get it? Read vertically: "AMD, why 9?").

 

[StinkyPinky]

I feel like the 7900 makes the 7900X redundant. If you want more multi-threaded power then it's the 7950X anyway, and if you want a nice mix of cores and gaming on a lower budget the 7900 seems like the no brainer choice over the 7900X.

 

[biostud]

I feel like the 7900 makes the 7900X redundant. If you want more multi-threaded power then it's the 7950X anyway, and if you want a nice mix of cores and gaming on a lower budget the 7900 seems like the no brainer choice over the 7900X.

Depending on were the retail price of the X processors go, there is no reason to get one over the none X parts.

 

[eek2121]

Depending on were the retail price of the X processors go, there is no reason to get one over the none X parts.

Depends on overclockabilty. The 7900X is faster out of the box.