MP 7.1 why not PCIe4 or 5???

Discussion in 'Mac Pro' started by thevault, Jun 7, 2019.

  1. thevault macrumors member

    thevault

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    #1
    Why is Apple not at least using PCIe4 in the new Mac Pro since what I've been reading is :

    "The PCIe standard maintains both backward and forward compatibility with older and newer specifications via both software and mechanical interface. In other words, PCIe 3.0 cards will work on motherboards that support PCIe 4.0, and PCIe 4.0 cards will also work on PCIe 3.0 motherboards, but they are limited to the performance of the PCIe 3.0 interface."
     
  2. tsialex macrumors 601

    tsialex

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    #2
    Simply because Intel don't have any CPU and support chips that have PCIe 4.0 yet.
     
  3. AidenShaw macrumors P6

    AidenShaw

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    #3
    ...and the number of PCIe 4.0 devices likely to ship in quantity this year can be counted on the fingers of one hand (and the thumb is not a finger).
     
  4. MagnumOP macrumors regular

    MagnumOP

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    #4
    I personally would LOVE PCIe 4.0, even if there are few options this year, they will expand going forward. I need super fast internal storage and PCIe 4.0 is nearly twice as fast.
     
  5. tsialex macrumors 601

    tsialex

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    #5
    PCIe 4.0 will probably be scrapped.

    It has so serious attenuation problems that today's AMD solution only works with one PCIe slot and needs to be exactly side by side with the CPU socket.
     
  6. now i see it macrumors 68040

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    #6
    It also gives  something to upgrade to in the future. They always hold back a bit on a new design to give them something "new" for the next generation.
     
  7. tsialex macrumors 601

    tsialex

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    #7
    Why they are holding onto something that don't exist yet? I'm failing to see it.
     
  8. deconstruct60, Jun 8, 2019
    Last edited: Jun 8, 2019

    deconstruct60 macrumors 604

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    #8


    1. The Mac Pro was probably originally designed and planned to finish in late 2018. There were no roadmaps of PCI-e v4 processors in late 2018. AMD or Intel. IBM Power was still going to be about the only player at that point when looking at projections back in late 2016 - early 2017.

    That the Mac Pro is sliding into 2019. It would have slide even more if they had to wait for 2019 targeted stuff engineering samples to get started. For a project that was 3-6 years late (depending upon perspective) that would have been an extremely dubious move. Complicated projects typically work much better when first get something solidly working done and then more on to incrementally more capable system. The Mac Pro had been completely dead-in-the-water for years.

    If Apple intends to put steady work into future Mac Pro then they'll merge in PCI-e bump on the next iteration. The primary issue was there was zero movement for years.


    2. PCIv4 is faster, but also more problematical. The lengths you can run PCIev4 lanes is shorter ( without having to re-transmit the signal. Which is more complicated board development.... which again more complicated typically leads to longer development time. )

    The new Mac Pro places the biggest bandwidth sockets the furtherest from the CPU. That is actually backwards from the normative that PCIe v4 constraints lean toward. It isn't a "show stopper" but it would have been yet another issue to deal with.

    3. Lots of folks were hoping that PCIe v5 would "clean up" some of the issues that v4 introduced. So that is why most folks waiting until v5 was closer to wrapping up before deploying v4. In the 2016-17 context v5 was still in early stages and could have possibly ended up getting stuck in committee ( few wanted that to happen but sometimes 'stuff happens' ) . Waiting on v5 was a significant risk increase.


    4. Intel was the 'safer bet' for the CPU. Yes their execution was problematical in 2016-2017 and the Meltdown, Spectre , and MDS security defect fest (in 2017-2018) is a problem for a company whose major marketing focus is security/privacy . But AMD had also shot themselves in the foot ( e.g., the GPU evolution sequence and the Mac Pro 2013 design). Intel didn't plan to do an aggressive rollout of PCIe v4 and when Apple picked them for the new Mac Pro , the Mac Pro was locked into that.

    Apple could have picked AMD and their PCIe v4 implementations, but it would have more so a "bet the farm" move. It would have guarantee that would slide into 2019 ( so even bigger group of impatient, pissed of user base). If AMD stumbled then could have ended up with components that were not competitive ( that's death at the 100+% increased entry price point they decided to shoot for).
    PCIev4 "everywhere" was going to put more thermal pressure on more components ( e.g., almost all of these AMD X570 boards have active coolers on the PCH. that isn't a "show stopper" but it is yet another placement and design problem to work around. )


    --- Post Merged, Jun 8, 2019 ---
    PCIe v4 isn't going to get scrapped any more than v3 , v2 or v1 were.

    PCIe v4 will probably stick around for a while because the main I/O hub chips (PCH) probably aren't going to go to v5. Even going to v4 is proving to be a stretch for the X570 chipsets (now needing active cooling. That will unwind a bit at the PCH more to better fab process and updated designs but v5 would just put that pressure back).

    The SerDes updates that v5 brings can be run at v4 speeds too. How to get to having something that actually needs v5 speeds in the vast commercial space is a problem. There are v4 PCIe M.2 drives but they all have to throw on more NAND chips ( 8 ) just to crank up the aggregate bandwidth from the NAND chips to fill the increased v4 headroom. Gaming doesn't saturate x16 v3 GPUs. x16 v4 is even less. There are some high end cases that have wins > 100GbE and shared/remote memory message/content passing. .... but much of that is smaller markets ( which is why hardly anybody followed IBM in implementing v4. Power9 was introduced back in 2017. It has been two years since first implementation and about three years since IBM rolled out beta machines to customers to test. )
    --- Post Merged, Jun 8, 2019 ---
    By different general product type or by number? By number all the 2019 AMD GPUs will have it. That is why AMD aggressively pushed it out the door on their CPUs to create bigger perceived synergy. (most of those will probably go into PCI-e v3 systems though). AMD is going a decent sales job of "we have it and they don't" .

    If dive into the "don't care how much it costs" Power9 cards can find a few there that have been shipping for a while.

    "by product type (in any price category)" . I wouldn't bet on that (less than 6). By late Fall there will probably be substantially more flow.
     
  9. Pressure macrumors 68040

    Pressure

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    #9
    That's with current motherboards. X570 have all PCIe 4.0 slots.

    We will see more than a handful PCIe SSDs with PCIe 4.0 x 4 support this year.
     
  10. vaugha, Jun 8, 2019
    Last edited: Jun 8, 2019

    vaugha macrumors 6502

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    #10
    I'm positive pcie 4.0 is coming to the mac pro in the coming years. Given the mac pro's ssd speed is subpar (~2.7/.6gbps write/read speeds respectively) and we're already seeing pcie 4.0 based nvme ssds w/ close to 5gbps read/write speeds, I will wait for the 2nd gen mac pro w/ upgraded specs.

    I want one and I'm going to have to sell my house to buy a decently spec'd out mac pro. Intel will follow suit to compete w/ amd and by then we should have the next gen xeons that support pcie 4.0 and hopefully pcie 4.0 based ssds. W/ amd releasing 3rd gen ryzen w/ pcie 4.0 support and other vendors starting to sell these ultra fast ssds, I don't think current mac pro is a good buy for me, at least not yet.
     
  11. deconstruct60 macrumors 604

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    #11
    Given Apple Mac Pro upgrade track record over the last decade I wouldn't be in the "positive" camp Current context it is crapshoot if there is another Mac Pro after this one. That Apple has slapped big fat margins on this system it has all the appearance of being mainly a cash cow. A cow that Apple could just milk for years while in Rip van Winkle mode in terms of new R&D work.

    Apple needs to do more "walking the walk" .... the "talk the talk" stuff isn't cutting it at this point. Less talk more do. This dog and pony show was just that a dog and pony show. It doesn't undo what they have done for the last decade.



    The MP 2019 has more that two x8 slots that someone could through x8 PCI-e card into and "RAID" some v3 M.2 to get to same bandwidth. (pragmatically that is all these early PCIe v4 ssds are doing. Packing two v3 components SSDs into one jam packed card. They all need more NAND chips to get the speed. ). The default boot drive is limited but is v4 really going to make a huge difference in common home directory usage and app load times? Probably not. [ There are folks who want to pile all of there 'mac volume' storage into one huge volume. but that isn't necessary on a Mac Pro, nor particularly desirable for a wide range of high performance workloads where the bandwidth makes a difference. ]
     
  12. vaugha macrumors 6502

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    #12
    While historically speaking you're right, I wouldn't rule out the other theory either. Target demographic is very different this time around and if they want to keep selling $20g - 50g systems to large corporations and the rich and alike, they will have to offer the latest protocols to compete. I just don't imagine them selling these down the road w/ the old v3 while the competitors have moved onto v4.
     
  13. Pressure macrumors 68040

    Pressure

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    #13
    They can't move faster than Intel. Unless ...
     
  14. Zdigital2015 macrumors 65816

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    #14
    Pretty sure PCIe 4.0 peripherals are going to need more power and more cooling than PCIe 3.0 devices - https://www.anandtech.com/show/14475/gigabytes-pcie-4-0-ssd-uses-77g-of-copper-due-to-8w-tdp

    If the PCH is generating too much heat, then I expect that Intel is going to have to do it with 14nm, once they get 10nm out in volume and can dedicate some 14nm (remember Intel’s PCH is on an N+1 schedule) fabs for production. And even then they made need a heat sink to cool it adequately.

    Silicon Motion won’t have their SSD controller out until Q2 2020 - https://www.anandtech.com/show/14433/silicon-motion-pcie-40-x4-ssd-controller-in-development - which is a big deal.

    Intel won’t release an update to Cascade Lake Xeon for at least another year, possibly longer depending on how well 10nm rollout goes later this year - https://wccftech.com/intel-xeon-roadmap-leak-10nm-ice-lake-sp-2020-sapphire-rapids-sp-2021/

    Consumer applications of PCIe 4.0 are going to take even longer to be released.

    PCIe 4.0 is not a near term thing right now and won’t be for a while.
     
  15. Pressure macrumors 68040

    Pressure

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    #15
    You can already buy graphic cards from AMD.
     
  16. Zdigital2015 macrumors 65816

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    #16
    Really? You can order one from New Egg or Amazon and have it delivered to your house in 2-3 days? Which one?
     
  17. vaugha macrumors 6502

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    #17
    I'm well aware of that. I don't think you read my previous post.
     
  18. Pressure macrumors 68040

    Pressure

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    #18
    VEGA 20, like the chip used in the Radeon Pro Vega II and Intinct MI50 and MI60.

    Next month NAVI.
     
  19. Zdigital2015 macrumors 65816

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    #19
    I won't split hairs over whether Radeon Instinct is a graphics card, but you are correct, it is PCIe 4.0, albeit high end. Even though it was supposed to be available in Q4/18, I have yet to find it for sale on the internet, but I am guessing this one is starting slow through OEMs and System Integrators who can sell it to a customer directly and we never see it hit the tubes.

    I will believe NAVI next month when I can order it from New Egg and get it in 2-3 days. And at that, all they introduced was one card...this roll out is taking forever.

    Again, PCIe 4.0 is going to be about 2 dozen devices for consumer sale at the end of the year and AMD motherboards, but is still going to be on the fringes for most consumers and quite a few pros.
     
  20. orph macrumors 68000

    orph

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    #20
    PCI 3 is here now and works, intel is here now and works.
    no one wants to hit problems with 'beta' drivers or first gen devices.

    Apple needs a stable fast computer with no big problems to get trust back, PCI 4 has not been proven in genral computers yet and there will be bugs.
    there's even bugs using some PCI 2 cards on PCI 3 slots (like some blackmagic cards).

    also apple must get a good deal with intel, no way will they mess that up by using AMD.

    and yes simply it's not on intelso now option :D next gen maybe
     
  21. AidenShaw macrumors P6

    AidenShaw

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    #21
    Well said.

    It's not fun being a guinea pig when it's your income that is at stake. Bus transitions take a long time before the kinks are ironed out and devices using the new bus are common.
     
  22. orph macrumors 68000

    orph

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    #22
    I relay think it's trust they need.

    I can relay see the problem of lack of trust, who wants to buy in to an echo system like the 2013 macpro. Must have been relay depresing for some waiting for the new update each year for it never to come, seeing GPU's die and no real upgrades :eek:
    if your the guy who got 50 2013 macpros for work and 3 year's later have to explain why you need 50 windows boxes :confused: nightmare land.

    i think the 2nd or 3rd gen new macpro will be the real winer if apple can keep kicking them out ever year or two.
     
  23. Pressure macrumors 68040

    Pressure

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    #23
    Screenshot 2019-06-11 at 00.22.37.png
     
  24. jscipione macrumors regular

    jscipione

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    #24
    Video cards don't matter for PCIe 4.0 because they typically go in a x16 slot anyway which has plenty of bandwidth to spare. With a Xeon you have so many lanes that PCIe 4 is irrelevant, the only time it matters is when you are limited to lanes and so have to make due with a pair of x8 slots. We are starting to reach the PCIe 3.0 x4 limit for SSDs so it is possible that there might be bandwidth limitations for future NVMe storage devices, but for now PCIe 3.0 is good enough. If you were paying attention you'd have known that PCIe 3.0 was a foregone conclusion in the Mac Pro 7,1 simply because Intel doesn't support PCIe 4.0 and AMD was never going to happen.
     
  25. ekwipt macrumors 6502a

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    #25
    AMD just announced a 16 Core CPU for $799... PCIE4 and people somehow stick up for the MacPro 8 Core at $6000

    But ECC RAM fam and 7 PCIe slots, it's a Pro it's not meant for you... blah blah blah

    16 Core TDP of 105
     

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