Apple is using a custom connector for the SSD in the new Mac Pro

Posted:
in Current Mac Hardware edited June 10
The new Mac Pro is a highly modular computer, making it ripe for upgrades and on-site servicing. But, the connector used for the built-in storage suggests replacements may have to be bought from Apple directly.




At the launch of the Mac Pro, Apple revealed there would be a number of options available for the built-in storage for the device. Starting from 256 gigabytes, Apple advised there were configurations that provided up to 4 terabytes of SSD storage, and to match the modular nature of the rest of the Mac Pro, the memory is also able to be removed and changed.

There are, however, questions about how serviceable the storage actually will be in reality, once it ships this fall.

What Apple says

The storage for the Mac Pro is made up of two separate sections: The SSD modules, and SATA expansion, with the latter previously explored by AppleInsider.

The flash storage modules will be offered in four different setups: One 256GB module, two 512GB modules for 1TB of total capacity, two 1TB modules for 2TB of capacity, and two 2TB modules for 4TB of capacity. Storage is encrypted by the T2 Security Chip, similar to other Mac models.

The storage section of the Mac Pro product page
The storage section of the Mac Pro product page


The performance of the modules is quoted as "up to 2.6GB/s sequential read and 2.7GB/s sequential write performance" meaning that this is effectively the same flash cells as used in the MacBook Pro.

Apple also supplies an image of two modules, illustrating that they are placed into the back portion of the Mac Pro, in the same compartment as the memory. But ultimately Apple stops short of saying what connector or technology is being used.

Pin counts and divisions

The information Apple provides isn't enough detail to confirm what kind of SSDs are being used by the Mac Pro, but what the image reveals is that it isn't any standard SSD that is in use with other devices.

An example of an M.2 connector
An example of an M.2 connector


The first thought is that it is an M.2 SSD of some description, as the body shape looks quite similar to that type of component. However, the way that the two sections of pins are divided is slightly closer to the center with Apple's SSDs, whereas M.2 connectors have a longer main section and a smaller secondary pin area, or two breaks in the connector.

It also doesn't use the same configuration as Optane memory, which is similar to M.2 except it has two small pin offshoots on either end with a long section in the middle.

An example of a connector used for Optane storage
An example of a connector used for Optane storage


The nearest in terms of the division's placement would be mSATA, which seems to have the right proportion between the two sections to match what is shown in the image. However, the number of pins shown seems to be different to what mSATA drives use.

An example of an mSATA connector
An example of an mSATA connector


A follow-up to M.2, the U.2 connection, formerly known as SFF-8639, is also not a possibility despite offering NVMe-style high-speed connectivity. Rather than having a break or a gap in the length of the connector, there is a thicker section that also includes pins that are raised away from the other two areas.

An example U.2 connector in an adapter
An example U.2 connector in an adapter


It also doesn't appear to be the same sort of connection Apple uses in some of its other products, as far as AppleInsider is aware. For example, the 13-inch MacBook Pro for late 2016 does have a removable SSD. However, while the proportions of the two sections of the connector are similar, the division has the opposite bias and effectively mirroring what the Mac Pro uses, ruling that one out.

Sources inside Apple not authorized to speak on behalf of the company say the drives do not use a standard M.2 pinout, but declined to speak about the slot's pin compatibility with older Apple SSD modules. This does leave open the possibility Apple is using a connector it previously created or has since modified.

It is highly likely that the connection is a proprietary one, very similar or identical to the iMac Pro, although though the exact details of pins, measurements, and other things won't be truly known until Apple ships the new Mac Pro, or some sort of support documentation leaks ahead of its release.

Performance

One way that we know that the drive cannot be mSATA, despite the closeness to the general shape, is the quoted performance of the drives.

At its core, mSATA can only provide SATA-level speeds at best, which can be up to 6 gigabits per second. Apple's speeds of around 2.6 gigabytes per second, and as SATA speed equals approximately 600 megabytes per second, this effectively rules out mSATA as a candidate.

NVMe drives are able to use the similar M.2 form factor, along with U.2, but are able to provide considerably higher read and write speeds than SATA SSDs, sometimes up to 3.5GB/s. Though unconfirmed, it is probable that these drives in particular use NVMe.

Upgrading Apple's drives

As Apple has established that the Mac Pro is a highly modular system, and that the included drives are also removable, it stands to reason that Apple will offer the opportunity to replace or even upgrade the drives after purchasing. This does leave open some questions, such as whether Apple will be the source of the replacements, will it offer drives separately for upgrades, or if aftermarket options will also be available.

Considering how Apple is using the T2 chip to secure these drives, it is likely to be in Apple's interests to provide upgrade options for these modules, or at the very least replacement drives for servicing, in order to maintain control over security.

Other upgrade avenues

These two storage modules are not the only route to upgrade the storage capacity of the Mac Pro. There are a few other methods that could be available to use, which may be more cost-effective than paying upfront for higher-capacity drives, as well as to expand the storage at a later time.

The main option is through SATA, using the two ports located high up on the main compartment. There aren't any extra drive bay slots or holders within the Mac Pro, so consumers will have to use aftermarket options, like those offered by Promise.

Part of the Mac Pro that includes two SATA connections, among others
Part of the Mac Pro that includes two SATA connections, among others


Those looking for high-speed storage may not want to use SATA due to the relatively low performance, but they are helpful as a last-ditch effort to add more capacity when all other avenues are exhausted.

A secondary method is to take advantage of the ample PCIe slots the Mac Pro offers, and to use it for storage. There are PCIe card adapters that can hold SSDs as well as NVMe, with the latter able to offer high-speed data transfers, along with cards with built-in storage.

An example PCIe adapter card that can be used with NVMe
An example PCIe adapter card that can be used with NVMe


A third option is to use MPX Modules, the hardware format that Apple introduced alongside the Mac Pro. While it has a main focus on high-powered GPUs, it is still effectively an enhanced PCIe system.

In the case of Promise, its Pegasus R4i is an MPX RAID module that contains four 7200 RPM drives, transferring data over PCIe while being powered by the MPX bay power header.

The Promise Pegasus R4i MPX Raid module
The Promise Pegasus R4i MPX Raid module


There is also the possibility of using external storage, taking advantage of the Thunderbolt 3 connections to access an external drive enclosure, albeit it is one that is likely to be used for projects confined to portable storage moved between workstations. Internal storage is usually desired more before turning towards external versions.
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Comments

  • Reply 1 of 98
    22july201322july2013 Posts: 667member
    This is the kind of article I like to see on AI. Some information, some analysis. A sprinkling of speculation.
    StrangeDayseightzeropscooter63cgWerkscornchipwatto_cobra
  • Reply 2 of 98
    dougddougd Posts: 252member
    Apple greed at work, they will charge 3x what other SSDs cost.
    freethinkingchemengin1tyler82elijahgdavgregairnerddysamoria1983SnickersMagooUrbaneLegend
  • Reply 3 of 98
    DuhSesameDuhSesame Posts: 557member
    That's one thing I'm concerned about the T2 because they bottleneck the SSD performance since both flash modules and controller keeps improving over time.  Judging by the iMac Pro, I'm sure those "SSDs" are just raw flash modules, whereas the T2 chip ties the controller within.  That limited any future performance improvement, but every computer with an M.2 running PCIe 3.0 have the potential to upgrade a faster SSD.

    Maybe that's not a problem for a Mac Pro, but certainly the iMac Pro and MacBook Pros.
    edited June 10
  • Reply 4 of 98
    hentaiboyhentaiboy Posts: 958member
    dougd said:
    Apple greed at work, they will charge 3x what other SSDs cost.
    Whatever the format, third parties will come out with an alternative.
    SoliStrangeDaysbb-15redgeminipallamathedarkhalf
  • Reply 5 of 98
    Mike WuertheleMike Wuerthele Posts: 4,604administrator
    DuhSesame said:
    That's one thing I'm concerned about the T2 because they bottleneck the SSD performance since both flash modules and controller keeps improving over time.  Judging on the iMac Pro, I'm sure those "SSDs" are just raw flash modules, whereas the T2 chip ties the controller within.  That limited any future performance improvement, but every computer with an M.2 running PCIe 3.0 have the potential to upgrade a faster SSD.

    Maybe that's not a problem for a Mac Pro, but not the iMac Pro and MacBook Pros.
    I'm not certain that they'll get that much faster. While the theoretical max speed of the PCI-E 3.0 x4 connector with a M.2 slot is 3600 megabytes per second or so, the reality is a bit less, perhaps 2900 megabytes per second.
    watto_cobra
  • Reply 6 of 98
    So, Apple wants the boot drive to be encrypted, and only an Apple drive will work.  After that, users are on their own...

    This kind of reduces the usefulness of the of the T2 chip... doesn’t it?

    The PCIe card with NVMe drives seems the “best” solution for high performance needs.  Then, maybe archive data to the Promise RAID.
  • Reply 7 of 98
    DuhSesameDuhSesame Posts: 557member
    DuhSesame said:
    That's one thing I'm concerned about the T2 because they bottleneck the SSD performance since both flash modules and controller keeps improving over time.  Judging on the iMac Pro, I'm sure those "SSDs" are just raw flash modules, whereas the T2 chip ties the controller within.  That limited any future performance improvement, but every computer with an M.2 running PCIe 3.0 have the potential to upgrade a faster SSD.

    Maybe that's not a problem for a Mac Pro, but not the iMac Pro and MacBook Pros.
    I'm not certain that they'll get that much faster. While the theoretical max speed of the PCI-E 3.0 x4 connector with a M.2 slot is 3600 megabytes per second or so, the reality is a bit less, perhaps 2900 megabytes per second.
    I don't think that's the case.  x4 should run at 3.9GB/s maximum and M.2 is just another form of it.  Source?

     https://www.pugetsystems.com/labs/articles/Overview-of-M-2-SSDs-586/
  • Reply 8 of 98
    Mike WuertheleMike Wuerthele Posts: 4,604administrator
    DuhSesame said:
    DuhSesame said:
    That's one thing I'm concerned about the T2 because they bottleneck the SSD performance since both flash modules and controller keeps improving over time.  Judging on the iMac Pro, I'm sure those "SSDs" are just raw flash modules, whereas the T2 chip ties the controller within.  That limited any future performance improvement, but every computer with an M.2 running PCIe 3.0 have the potential to upgrade a faster SSD.

    Maybe that's not a problem for a Mac Pro, but not the iMac Pro and MacBook Pros.
    I'm not certain that they'll get that much faster. While the theoretical max speed of the PCI-E 3.0 x4 connector with a M.2 slot is 3600 megabytes per second or so, the reality is a bit less, perhaps 2900 megabytes per second.
    I don't think that's the case.  x4 should run at 3.9GB/s maximum and M.2 is just another form of it.  Source?

     https://www.pugetsystems.com/labs/articles/Overview-of-M-2-SSDs-586/
    Their numbers aren't including overhead for the PCI-E connection itself. Best case, that overhead is 10%, thus the 3600 megabytes per second.
  • Reply 9 of 98
    mretondomretondo Posts: 79member
    hentaiboy said:
    dougd said:
    Apple greed at work, they will charge 3x what other SSDs cost.
    Whatever the format, third parties will come out with an alternative.
    OWC
    thedarkhalffastasleepwatto_cobra
  • Reply 10 of 98
    DuhSesameDuhSesame Posts: 557member
    DuhSesame said:
    DuhSesame said:
    That's one thing I'm concerned about the T2 because they bottleneck the SSD performance since both flash modules and controller keeps improving over time.  Judging on the iMac Pro, I'm sure those "SSDs" are just raw flash modules, whereas the T2 chip ties the controller within.  That limited any future performance improvement, but every computer with an M.2 running PCIe 3.0 have the potential to upgrade a faster SSD.

    Maybe that's not a problem for a Mac Pro, but not the iMac Pro and MacBook Pros.
    I'm not certain that they'll get that much faster. While the theoretical max speed of the PCI-E 3.0 x4 connector with a M.2 slot is 3600 megabytes per second or so, the reality is a bit less, perhaps 2900 megabytes per second.
    I don't think that's the case.  x4 should run at 3.9GB/s maximum and M.2 is just another form of it.  Source?

     https://www.pugetsystems.com/labs/articles/Overview-of-M-2-SSDs-586/
    Their numbers aren't including overhead for the PCI-E connection itself. Best case, that overhead is 10%, thus the 3600 megabytes per second.
    It's actually around 1.54% for PCIe 3.0, so 985MB/s.  You got 3.9GB/s when it times four.

    https://www.tested.com/tech/457440-theoretical-vs-actual-bandwidth-pci-express-and-thunderbolt/
    https://www.overclock.net/forum/355-ssd/1489684-ssd-interface-comparison-pci-express-vs-sata.html

    But whether it's 3.6 or 3.9, it left both the iMac Pro and MacBook Pros lots of room for improvement.
  • Reply 11 of 98
    thttht Posts: 3,212member
    Looks like the same NAND cards in the iMac Pro:

    FileMakerFellertenthousandthingsdysamoriathedarkhalfcamccornchipwatto_cobra
  • Reply 12 of 98
    maltzmaltz Posts: 134member
    hentaiboy said:
    dougd said:
    Apple greed at work, they will charge 3x what other SSDs cost.
    Whatever the format, third parties will come out with an alternative.
    A scant few, if any, compared to if they'd just use the existing standard though. Then you'd have the whole industry's worth of options. I'd really like to hear the justification for this ridiculousness. (Other than charging literally 2-3x the retail rate for SSD storage, if it follows the trend in other Macs.) It's not like this is even any thinner than an M.2 card - not that it should matter in a tower case.
    muthuk_vanalingamdysamoria
  • Reply 13 of 98
    sflocalsflocal Posts: 4,624member
    dougd said:
    Apple greed at work, they will charge 3x what other SSDs cost.
    Buzz off hater.  

    No one knows anything until Apple starts shipping these.  I will give Apple the benefit of doubt then wait and see what the actual information says.  I suspect 3rd party vendors will have Apple-compatible drives.
    bb-15StrangeDaysJWSCrob53pscooter63kevin keefastasleepwatto_cobra
  • Reply 14 of 98
    rhymanrhyman Posts: 3member
    Actually, these images of storage for the Mac Pro appear to have connectors very similar to the connectors for SSDs in MacBook Pros going back at least to 2016. MacTracker states them to be 8.0 GT/s NVMe PCIe x4 The pin count as best I can tell, also seems to be very similar. So, getting SSDs for the Mac Pro may not be a problem at all.
    watto_cobra
  • Reply 15 of 98
    Mike WuertheleMike Wuerthele Posts: 4,604administrator
    DuhSesame said:
    DuhSesame said:
    DuhSesame said:
    That's one thing I'm concerned about the T2 because they bottleneck the SSD performance since both flash modules and controller keeps improving over time.  Judging on the iMac Pro, I'm sure those "SSDs" are just raw flash modules, whereas the T2 chip ties the controller within.  That limited any future performance improvement, but every computer with an M.2 running PCIe 3.0 have the potential to upgrade a faster SSD.

    Maybe that's not a problem for a Mac Pro, but not the iMac Pro and MacBook Pros.
    I'm not certain that they'll get that much faster. While the theoretical max speed of the PCI-E 3.0 x4 connector with a M.2 slot is 3600 megabytes per second or so, the reality is a bit less, perhaps 2900 megabytes per second.
    I don't think that's the case.  x4 should run at 3.9GB/s maximum and M.2 is just another form of it.  Source?

     https://www.pugetsystems.com/labs/articles/Overview-of-M-2-SSDs-586/
    Their numbers aren't including overhead for the PCI-E connection itself. Best case, that overhead is 10%, thus the 3600 megabytes per second.
    It's actually around 1.54% for PCIe 3.0, so 985MB/s.  You got 3.9GB/s when it times four.

    https://www.tested.com/tech/457440-theoretical-vs-actual-bandwidth-pci-express-and-thunderbolt/
    https://www.overclock.net/forum/355-ssd/1489684-ssd-interface-comparison-pci-express-vs-sata.html

    But whether it's 3.6 or 3.9, it left both the iMac Pro and MacBook Pros lots of room for improvement.
    Huh, TIL.

    Still, there is NVMe storage overhead too. I just don't think there's as much leeway for growth as you do, is all.
  • Reply 16 of 98
    Mike WuertheleMike Wuerthele Posts: 4,604administrator

    rhyman said:
    Actually, these images of storage for the Mac Pro appear to have connectors very similar to the connectors for SSDs in MacBook Pros going back at least to 2016. MacTracker states them to be 8.0 GT/s NVMe PCIe x4 The pin count as best I can tell, also seems to be very similar. So, getting SSDs for the Mac Pro may not be a problem at all.
    It isn't even close between the two, and that SSD was only on the 2016 13-inch MacBook Pro. As the article says, and other commenters, it is closest to the iMac Pro.
    edited June 10 watto_cobra
  • Reply 17 of 98
    DuhSesameDuhSesame Posts: 557member
    DuhSesame said:
    DuhSesame said:
    DuhSesame said:
    That's one thing I'm concerned about the T2 because they bottleneck the SSD performance since both flash modules and controller keeps improving over time.  Judging on the iMac Pro, I'm sure those "SSDs" are just raw flash modules, whereas the T2 chip ties the controller within.  That limited any future performance improvement, but every computer with an M.2 running PCIe 3.0 have the potential to upgrade a faster SSD.

    Maybe that's not a problem for a Mac Pro, but not the iMac Pro and MacBook Pros.
    I'm not certain that they'll get that much faster. While the theoretical max speed of the PCI-E 3.0 x4 connector with a M.2 slot is 3600 megabytes per second or so, the reality is a bit less, perhaps 2900 megabytes per second.
    I don't think that's the case.  x4 should run at 3.9GB/s maximum and M.2 is just another form of it.  Source?

     https://www.pugetsystems.com/labs/articles/Overview-of-M-2-SSDs-586/
    Their numbers aren't including overhead for the PCI-E connection itself. Best case, that overhead is 10%, thus the 3600 megabytes per second.
    It's actually around 1.54% for PCIe 3.0, so 985MB/s.  You got 3.9GB/s when it times four.

    https://www.tested.com/tech/457440-theoretical-vs-actual-bandwidth-pci-express-and-thunderbolt/
    https://www.overclock.net/forum/355-ssd/1489684-ssd-interface-comparison-pci-express-vs-sata.html

    But whether it's 3.6 or 3.9, it left both the iMac Pro and MacBook Pros lots of room for improvement.
    Huh, TIL.

    Still, there is NVMe storage overhead too. I just don't think there's as much leeway for growth as you do, is all.
    I've talked to a friend about this and he thinks the T2 is better optimized for APFS.  That might be true, but I'm not sure some software improvements will overcome hardware advancements.

    Then again, I know nothing about SSD controllers.  All of them could have different architectures.
    edited June 10
  • Reply 18 of 98
    melgrossmelgross Posts: 31,697member
    DuhSesame said:
    DuhSesame said:
    DuhSesame said:
    DuhSesame said:
    That's one thing I'm concerned about the T2 because they bottleneck the SSD performance since both flash modules and controller keeps improving over time.  Judging on the iMac Pro, I'm sure those "SSDs" are just raw flash modules, whereas the T2 chip ties the controller within.  That limited any future performance improvement, but every computer with an M.2 running PCIe 3.0 have the potential to upgrade a faster SSD.

    Maybe that's not a problem for a Mac Pro, but not the iMac Pro and MacBook Pros.
    I'm not certain that they'll get that much faster. While the theoretical max speed of the PCI-E 3.0 x4 connector with a M.2 slot is 3600 megabytes per second or so, the reality is a bit less, perhaps 2900 megabytes per second.
    I don't think that's the case.  x4 should run at 3.9GB/s maximum and M.2 is just another form of it.  Source?

     https://www.pugetsystems.com/labs/articles/Overview-of-M-2-SSDs-586/
    Their numbers aren't including overhead for the PCI-E connection itself. Best case, that overhead is 10%, thus the 3600 megabytes per second.
    It's actually around 1.54% for PCIe 3.0, so 985MB/s.  You got 3.9GB/s when it times four.

    https://www.tested.com/tech/457440-theoretical-vs-actual-bandwidth-pci-express-and-thunderbolt/
    https://www.overclock.net/forum/355-ssd/1489684-ssd-interface-comparison-pci-express-vs-sata.html

    But whether it's 3.6 or 3.9, it left both the iMac Pro and MacBook Pros lots of room for improvement.
    Huh, TIL.

    Still, there is NVMe storage overhead too. I just don't think there's as much leeway for growth as you do, is all.
    I've talked to a friend about this and he thinks the T2 is better optimized for APFS.  That might be true, but I'm not sure some software improvements will overcome hardware advancements.

    Then again, I know nothing about SSD controllers.  All of them could have different architectures.
    There are over a half dozen major SSD  controller architectures out there. New ones come around every year or two.
    bb-15watto_cobra
  • Reply 19 of 98
    sergiozsergioz Posts: 230member
    You are silly if you thought it was going to be any other way!
    dysamoriaelijahg
  • Reply 20 of 98
    StrangeDaysStrangeDays Posts: 7,625member
    dougd said:
    Apple greed at work, they will charge 3x what other SSDs cost.
    I really doubt that. Apple has shown time & again that their engineers lead with what they believe is the best solution for the product. The pundits and rumormongers just come up with their own invented reasons, which are conjecture only. 
    rob53kevin keecornchipfastasleepwatto_cobra
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