New Zen microarchitecture details

Discussion in 'CPUs and Overclocking' started by Dresdenboy, Mar 1, 2016.

  1. deasd

    deasd Member

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    When you go from x32 to SSE and even to AVX and resulting performance boost, I'm afraid there's no so-call IPC optimized factor here. If you have wider pipeline and load/store, you could often have higher performance even if your 'IPC' is the same. So your calculation might not accurate.

    EDIT:[sarcasm]I would rather believe Zen to be 40% faster than Excavator in Superpi.[/sarcasm]
     
    #1726 deasd, Jun 3, 2016
    Last edited: Jun 3, 2016
  2. Zstream

    Zstream Platinum Member

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    Yeah, I read that wrong lol. Isn't SMT performance going to be the same for Intel as AMD? I mean, it's just using leftover resources on that core, right? So, if a hardware core is at 70% utilization, SMT can only provide 30% on that logical OS core (considering all things equal and evenly split).
     
  3. frozentundra123456

    frozentundra123456 Diamond Member

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    If the only can reach SB IPC, I would consider that a fail. They need at least something between IB and HSW ipc.

    8 cores at Sandy Bridge IPC, assuming it can reach the same clocks as BW-E (which is *far* from a given, and highly doubtful in my mind) would be similar to 6 core BW-E, maybe slightly faster in workloads that can use all the cores, slower in everything else. So it is competitive only if the price is right. They really need better than that though to slot closer to 8 core intel, since there is such a huge price gap between intel 6 and 8 core chips. Of course there could be considerably savings on the motherboard compared to intel, so that could make the chip more price competitive.
     
  4. jpiniero

    jpiniero Diamond Member

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    From a practical standpoint though SB IPC would be good enough to be GPU limited in most games though assuming the clocks are not terrible. Look at where the 6 Core SB-E lands in most games that are really well threaded - maybe not at the top but very close.
     
  5. DrMrLordX

    DrMrLordX Diamond Member

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    Okay . . .

    Why? Intel has had better stuff than that on the market since at least the 5960X. The only thing it would have going for it is the 95w TDP.

    It's better than Vishera but it's not better than what AMD could have come up with had they just kept iterating on Construction cores.
     
  6. nenforcer

    nenforcer Golden Member

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    This is a drastically different architecture when compared to the Construction cores - we'll really have to wait for individual benchmarks on both the Integer and Floating Point units to know for sure.
     
  7. IntelUser2000

    IntelUser2000 Elite Member

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    Not that simple.

    Pentium 4's SMT was at a higher level same as Skylake's SMT. However, the details made all the difference. Pentium 4's SMT was effective enough by Northwood C generation, but there still were fair bit of cases where it was good turning it off. With Skylake that's almost nonexistent.

    That's why Stilt is saying that Intel has 12 years of real-world experience. Delays and missteps happen likely because what you planned(or theorized) don't pan out in reality.

    IBM's Power 8 chips have fantastic clock speeds and multi-threading performance, but per clock Intel chips still have the lead by a decent margin. And consumer workloads requirements are very different from server. A certain subsection of people would cry out for 2% degradation in single thread if Intel decided to use 4-way SMT to improve multi-threading performance by 10%.

    CPU workloads can't be characterized by improving a single unit. Intel's overall architecture is well-balanced which is why they fare well regardless of whether it's FP or Integer.

    Of course, there's no doubt AMD will be far closer to Intel than ever. But will have closed the gap because they are more competent than Intel or because its just diminishing returns at that point?
     
  8. KTE

    KTE Senior member

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    So what's your expectation from what you know so far?


    Even if Zen came with an average +65% performance gain over Excavator (a huge unknown), it would need matching Price, Power and Frequencies to what Intel offers by Q1 2017 to be competitive, recommendable and sell. It would also need to have mass availability, mainly through OEMs, by Q4 2016.

    The odds are highly stacked.

    Sent from my HTC 10 using Tapatalk
     
  9. The Stilt

    The Stilt Golden Member

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    The base frequency will be limited by the TDP (that's the whole point of having Turbo), but how low will it end up being is matter of the characteristics of 14nm LPP process. 14nm LPP is extremely power efficient at it's optimal operating window, but the question is at what rate does the efficiency deteriorate as the frequency stretches out of the window.

    I would expect the base frequency to be 2.8GHz (±200MHz) for the fastest Zeppelin SKU (8C/16T, 95W).

    AMD has been so far behind in process technology for years that they have had to develop extremely efficient power management in order to compensate the process deficiency the best they can. I personally rank the power management on Carrizo and newer designs much higher than Intel's, in terms of efficiency and features. Zen should be using pretty much identical PM as Excavator (CZ/BR/ST), with some generational improvements of course (directly related to frequency). I expect the maximum boost frequency to settle in the 3.6GHz range (±100MHz) and that the maximum boost is available to two cores (with or without SMT enabled) simultaneously. Due the way the PM works in Excavator based designs and the changes AMD made to it in Zen, I expect the average frequency to vary quite a lot depending on the workload and the number of utilized cores / CCXs.

    So far I think I've said anything between 2.6GHz - 3.2GHz as the base and anything between 3.2GHz - 3.8GHz for the maximum boost.

    However I stick with 2.8GHz (±200MHz) for the base and 3600MHz (±100MHz) for the maximum boost. I also do expect that AMD will release the Zeppelin AM4 SKUs clocked "balls to the wall" in terms of the default boost frequency. The extremely strict VRM requirements and the new extremely precise frequency control method point in this way.

    Higher TDP would naturally allow higher base frequencies but not boost frequencies, which I expected to be limited by the manufacturing process.

    With "not able to hit higher than x" I mean the frequencies AMD can actually ship the parts at (as a normal, consumer grade SKU), and not the frequencies some halfwit can hit while supplying 1.6V to the CPU, making it consume 310W.
     
  10. el etro

    el etro Golden Member

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    How the processor will achieve different turbo speeds for 1C and for 8C? Aggressive power management of couse!
     
  11. The Stilt

    The Stilt Golden Member

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    It is pretty silly to have 8C "turbo frequency". Usually it is called as base :sneaky:
     
  12. KTE

    KTE Senior member

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    And IPC wise?

    Jumping to TSMCs 10nm process might be worthwhile for AMD.


    Sent from HTC 10
     
  13. JDG1980

    JDG1980 Golden Member

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    The 5960X is a $1000 CPU with a 140W TDP. If AMD can offer 70%-80% of the MT performance and 80%-90% of the ST performance, in a 95W package at a $299-$399 price point, that's going to get a lot of takers.

    For reference, the going rate on eBay for a used Sandy Bridge E5-2687W CPU (8C/16T, 3.1 GHz base, 3.8 GHz turbo) is about $350. That has a TDP of 150W and requires an expensive LGA 2011 motherboard- not to mention that it comes with no warranty or support of any kind. You don't think that kind of performance at 95W on a fully supported modern platform would sell decently at the right price?

    Hard to prove a hypothetical, but all the signs point to the construction cores having fundamental, unfixable structural problems. Everything we've seen indicates they were simply inferior designs. Even after four iterations (BD->PD->SR->XV), IPC is still hardly up to par with Conroe and Thuban, and well behind Nehalem.
     
  14. JDG1980

    JDG1980 Golden Member

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    Do we know for a fact that Summit Ridge will in fact be manufactured on GloFo 14LPP? AMD has generally been careful to mention only "FinFET" in its marketing materials, not any specific process.

    I agree it's most likely they will do that, but if the GloFo process turns out to be completely unsuitable for high frequency CPUs, then there is still the possibility they could go with TSMC 16FF+ for the flagship Zen products, and fill their WSA quota with GPUs and console APUs.

    I can't find the exact quote, but I remember an interview with Tom's Hardware where Lisa Su said that Zen was a "bet-the-company" product. I don't think they are going to let an unsuitable process node drag that down. And I don't think they will release the flagship Summit Ridge product with a base clock below 3.0 GHz at a minimum.
     
  15. LTC8K6

    LTC8K6 Lifer

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    IIRC, some Intel chips have an all core turbo frequency that is above the base clock. My 1231 V3 at stock seems to have a 3.4 base, 3.6 all core turbo, 3.8 single core turbo, for example.

    4790K at stock seems to be 4.0 base, 4.2 turbo on all cores, and 4.4 turbo on one core.
     
  16. jpiniero

    jpiniero Diamond Member

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    It's possible but AFAIK it was in relation to the GPUs and not necessarily any CPU or APU.
     
  17. sirmo

    sirmo Senior member

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    They probably have a pretty good understanding of the Samsung 14nm LPP process, based on specs. They don't only have a WSA with Global Foundries for it, they also have one with Samsung directly, so they can fab Zen at GloFo or Samsung. I think the reason they are moving all their designs to 14nm LPP is for their semi custom business, this allows them the ability to use the same exact design in both fabs. The semi custom customer configures a SoC from AMD's IP blocks (including the Zen cores) and they can fab it in either fab.

    Using 16nm would require them to have to design all their components (GPUs, Zen core, uncore...) for different processes which is double the work. They don't have Apple money to waste and do that.
     
    #1742 sirmo, Jun 4, 2016
    Last edited: Jun 4, 2016
  18. ShintaiDK

    ShintaiDK Lifer

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    AMD doesn't have a WSA with Samsung. And thank god for that, its bad enough they got one with Glofo.

    There is nothing pointing to "dual sourcing" either.
     
  19. coffeemonster

    coffeemonster Member

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    what are you basing that on? that is wildly contradictory to what has already been shown in the carizzo/bristol ridge threads.
     
  20. The Stilt

    The Stilt Golden Member

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    Some of the older slides say 14nm FinFet. Since only Intel and Samsung / GlobalFoundries have 14nm process available... I don't know if has been announced in public, but the process is GlobalFoundries 14nm LPP to be specific. Made in Fab 8 NY.

    Sure, AMD could definitely port Zeppelin to 16nm FF+ if necessary...
    However that would add anything between 6-12 months of additional delay, and cost millions.
     
  21. frozentundra123456

    frozentundra123456 Diamond Member

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    You wouldnt have thought they would let a flawed architecture drag down Bulldozer, but they did. By your reasoning, no company would ever release a bad product.
     
  22. sirmo

    sirmo Senior member

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    http://forums.anandtech.com/showthread.php?t=2458413

    AMD has a long standing WSA with GloFo till 2019. They also have a WSA with TSMC for 28nm console and GPU chips. And that story I linked points to a WSA with Samsung.
     
    #1747 sirmo, Jun 4, 2016
    Last edited: Jun 4, 2016
  23. ShintaiDK

    ShintaiDK Lifer

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  24. el etro

    el etro Golden Member

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    No. Usually is called "How far it can go based on power and temperature limits". Like Nvidia and AMD GPUs does.
     
  25. sirmo

    sirmo Senior member

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    Correction, you're right it is in 2024. WSA is just a generic term for a contract with a fab. I just linked you to the story that says they have it with Samsung? Are you disputing the validity of the source or what? I am confused.