Discussion Zen 5 Speculation (EPYC Turin and Strix Point/Granite Ridge - Ryzen 9000)

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Jan Olšan

Senior member
Jan 12, 2017
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So regarding the 0% SpecInt improvement that AnandTech got, I think it would be good to put in context of the test setup they are using. They mention they are using WSL, but don't mention the type [WSL1 vs WSL2, with 1 being a sort of emulation layer, 2 being a VM running Linux Kernel, and the default nowadays] plus rather old Clang version. In comparison David Huang used native Linux environment and more modern version of gcc, but its worth noting that in both setups compiler will not generate AVX512 instructions afaik.

Now, why that might be important is if they are using WSL the core pinning might not work as expected so you might not measure what you expect to measure. Especially when dealing with hybrid architectures. I am not familiar with internals of Spec, but I would expect that 1T run should be pinned to the core either by spec runtime itself or by the person running Spec for meaningful results.

That plus difference in compilers used might explain why AT measures 7.01 Spec rate for Zen4 but Huang is seeing 8.45 for a core locked at 4.8 GHz if I understand his table correctly. Correspondingly he measures 9.27 for Zen5 vs 7.02 AT got.

Now I am just trying to understand why AT result is different than what other test seems to suggest [GeekBench INT improvement is also better than 0, especially the compiler subtest of geekbench that could be used as a proxy of broad integer workload stressing different parts of the core, is showing something in the ballpark of low but cositient improvement ].

The encoding test are also all over the place (looking at AV1), with there being large gap between Phoenix and Strix and then the difference gets swapped in the same test but different resolution? Feels like something doesn't quite work in the scheduling or in clock management. Could also be SVT having awful threading model perhaps. AV1 encoding via Handbrake seemed to suck in ComputerBase review too, perhaps the encoder sucks on big.little (although in massively threaded up, it should effectively stop being big.little except for the caches). Maybe the encoder is prone to some problem with threading or dispatching SIMD on zen 5 / strix for some reason.
 
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naukkis

Senior member
Jun 5, 2002
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The encoding test are also all over the place (looking at AV1), with there being large gap between Phoenix and Strix and then the difference gets swapped in the same test but different resolution? Feels like something doesn't quite work in the scheduling or in clock management. Could also be SVT having awful threading model perhaps.

I except that many workloads won't schelude right with that odd asymmetric CCX configuration. For games - limit them to 4 core CCX or results will probably be beyond terrible.
 

HurleyBird

Platinum Member
Apr 22, 2003
2,759
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I except that many workloads won't schelude right with that odd asymmetric CCX configuration. For games - limit them to 4 core CCX or results will probably be beyond terrible.

Kind of looks that way. Hopefully gets ironed out with later BIOS and Windows updates. Intel was able to solve an even more difficult scheduling problem.

Still, how stupidly safe AMD plays their cards is frustrating. Seems like they will sacrifice elegance on the alter of execution every time (and then get delayed anyway for other reasons). An odd mix of overly aggressive in some areas, and overridingly cautious in others.

"Let's lego this die together to get it out faster. Who cares if we're wasting like 15mm2 on a consumer product that we're going to ship millions of! Cadence is king!"

"Let's do 2 CCXes for this, with very little L3 on one of them, even though we can do 16-core CCXs now, and we've mixed and match full fat and dense cores on the same CCX before, because a 12-core CCX that mixes and matches will require some amount of additional work that might delay the product. Because of this, we will sacrifices some performance, creates a minor scheduling nightmare, and balloon the die size a bit.... But it's worth it because cadence is king!"

"Let's do a stupidly massive architectural change, with a bunch of super novel crap and--hey guys, think we can develop it on two nodes at the same time? Leeeeroy Jenkiiiiinnnsss!"
 
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inf64

Diamond Member
Mar 11, 2011
3,863
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Interesting post by David Huang;


"The consequence of Zen 5's initial release to most media outlets for testing on ultra-thin notebooks is that you can't even find a few Cinebench tests where a single core ran at full frequency without being throttled..."

No wonder AT couldn't measure any ST IPC increase in Specint while David measured around 10% jump vs Zen 4 mobile part.

Another comment (spicey language):


edit;
One more


"I suggest you wait until I finish running SPEC and GB under Linux in a few days before drawing any conclusions.In addition, if you have read my previous analysis of performance bottlenecks, you will know that even for a 6-wide 4ALU x86 processor, the performance bottleneck is mostly not in the decoding width or the number of ALUs."
 
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FlameTail

Diamond Member
Dec 15, 2021
3,746
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Come in here, and people are calling it "Bulldozer 2.0" and s**t posting everywhere.. what the hell happened to this place? , it's like Circus sometimes.
So Zen5 = Bulldozer 2.0?

Fascinating.
I'm amazed that this comment got jumped on (-7 downvotes? ).

I made that comment in the context of a few people discussing how some of Zen5's architectural changes seemed questionable (which could also be said of Bulldozer).

Of course, Zen5 is literally not a Bulldozer 2.0. If you see the following two replies, you can see that I agree with what they say (I was one of the first to like both comments).
Not in the sense of being a completely uncompetitive product. It looks like AMD made some odd choices, tried some new tricks, and performance is kind of underwhelming, but it's not meaningfully worse than Zen4 on any axis and is better on some others.

Folks making the Dozer comparison need to remember that Intel was doing 50%+ more iso-clock ST int against it.
Uhhh, no. No where near the same.
As you can see, my objective with the comment was to incite further discussion about those questionable architectural changes in Zen5. I had no ill intention of annoying anybody/trolling, but I admit my words were poorly chosen, and that may have inadvertently offended many people.

So hereby, I sincerely apologise to all of you
 

Tuna-Fish

Golden Member
Mar 4, 2011
1,474
1,958
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Since there has been made som z790 boards with camm2 slots does AM5 chips in theory supports camm2 modules or will it require a new CCD/memory controller and socket?

CAMM is a connector/interface standard, and requires no changes in the CPU. Any CPU that can support DDR5 can in principle be with a DDR5 CAMM2 board, any CPU that can support LPDDR5X can in principle be used with a LPDDR5X CAMM2 board.
 

poke01

Golden Member
Mar 8, 2022
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"I suggest you wait until I finish running SPEC and GB under Linux in a few days before drawing any conclusions.In addition, if you have read my previous analysis of performance bottlenecks, you will know that even for a 6-wide 4ALU x86 processor, the performance bottleneck is mostly not in the decoding width or the number of ALUs."
There are very few people in the media/online who can conduct proper SPEC tests and David is one of those people.
 

FlameTail

Diamond Member
Dec 15, 2021
3,746
2,184
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Figures I've saw being throwed some time ago was around 170 - 180mm²

It comply with the Microsoft marketing point, it will be featured into newer designs and with more design wins, it will have a branding that indicates it's a new generation part
certainly.
and will also slot into a cheaper price bracket than HWK.
That I am not sure about. Phoenix/Hawk Point laptops have gotten much cheaper since they launched. And if Kraken is indeed 170-180 mm², then it's pretty much the same die area as PHX/HWK (178 mm²).

Edit: This leaked slide may give some insight:
 
Reactions: lightmanek

Josh128

Senior member
Oct 14, 2022
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Matches AMDs claims. They claimed 22% better MT in Blender which has 23% IPC. So in CB23 which has 17% IPC there should be a 16-17% uplift. 7950X scores 38.7k so it fits exactly.
Certainly PBO or a manual OC though. If it achieved it at 230W, its so odd that AMD chose to require PBO to reach that perf instead of letting the proc handle it itself. Only thing I can think of is its a reliability/culpability play, and the voltage and current requirements to hit this ~45K are just not something they are comfortable having to warranty.
 
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