Two of four Thunderbolt 3 ports in new 13" MacBook Pro with Touch Bar have reduced speeds

Posted:
in Current Mac Hardware edited October 2016
A support document published by Apple on Friday reveals only two of the four Thunderbolt 3 ports in the latest 13-inch MacBook Pro with Touch Bar support full-speed data transfer, potentially limiting the notebook's flexibility for power users.




Apple in a Support Pages document covering Thunderbolt 3 connectivity says late-2016 MacBook Pro port data speeds "vary slightly" depending on the model. Of note, the 13-inch version with Touch Bar delivers full PCI Express bandwidth, and thereby lower throughput, to only two of its four ports.

Specifically, the two ports on the notebook's right hand side provide full Thunderbolt 3 functionality, but have reduced bandwidth, while the left pair retains full PCIe throughput. For this reason, Apple recommends connecting high performance peripherals like fast Thunderbolt 3 RAID arrays via the left-hand ports.

By comparison, the more powerful 15-inch MacBook Pro model supports full PCIe bandwidth on each of its four Thunderbolt 3 ports, as does the 13-inch MacBook Pro without Touch Bar for its two ports.

As AppleInsider noted in a deep dive into Thunderbolt 3 earlier today, the new MacBook Pro with Touch Bar models incorporate two Thunderbolt 3 controller chips.

The exact setup remains unclear at this time, but the latest hardware likely employs a version of Intel's Alpine Ridge controller and chipset. Intel currently lists multiple variations of Alpine Ridge in single-port, dual-port and low-energy SKUs, each with a different number of PCIe lanes. A single lane is defined as a pair of unidirectional signaling connections that in a PCIe bus work together to deliver full duplex communication. These lanes determine how much data can flow through a PCIe link, and are likely behind the 13-inch MacBook Pro's specs.

Considering the 13- and 15-inch MacBook Pro with Touch Bar offerings are able to run a 5K display -- two 5K or four 4K monitors on the 15-inch model -- Apple is thought to be using a pair of dual-port controller chips on both versions. What remains unclear, however, is whether the controller chips are identical. From the support document, it appears that either the 13- and 15-inch Thunderbolt 3 controllers have a different number of PCIe lanes or, more likely, that the 13-inch model's bottleneck is external to the chipset.
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Comments

  • Reply 1 of 86
    SoliSoli Posts: 9,272member
    What would the cost difference be for a 2nd controller? How large is this controller?
  • Reply 2 of 86
    The user and all related content has been deleted.
  • Reply 3 of 86
    cpsrocpsro Posts: 2,490member
    The ports on the right will the perfect mate for the iPhone 8 with its USB-C.
    edited October 2016 baconstang1983
  • Reply 4 of 86
    19831983 Posts: 1,192member
    Why? Here we go again Apple crippling the 13" Pro's spec in comparison to the ridiculously more expensive 15" version. Even though they're both very expensive laptops to begin with. They give you something good with one hand, slap you in the face with the other. The 15" already has a lot of power user advantages over the 13", they could of at least given the 13" 4 'proper' TB3 ports.
    singularitydysamoriaperkedel
  • Reply 5 of 86
    Redefining 'pro' again.
    tallest skildysamoriaaylk
  • Reply 6 of 86
    adonissmuadonissmu Posts: 1,772member
    You aren't going to be able to fully power all 4 ports with the dual core processor in the 13" MBP. Sorry folks. They are simply not powerful enough. They won't be for awhile because of heat, battery life and other concerns that would take more precedent over a slightly less powerful USBC port on the right hand side of a machine. I guess they probably could've just had 1 port on the right side instead but people would've complained then too is my guess.  
    2old4funstevehkamiltonPolyphoniesmaceslinmagman1979randominternetpersonindyfxanomenolamacguy
  • Reply 7 of 86
    Could it be a power consumption issue?

    I don't see how they could save money on this. A couple of dollars maybe? The cost for the integration of a different chip set, would seem to offset potential savings.

    And it's not something that can be used in marketing either because it's over most people's heads... it will make for unhappy customers AFTER they bought it and realize the limitation. So unless there's a technical reason, this would be a stupid move.
    edited October 2016
  • Reply 8 of 86
    fracfrac Posts: 480member
    1983 said:
    Why? Here we go again Apple crippling the 13" Pro's spec in comparison to the ridiculously more expensive 15" version. Even though they're both very expensive laptops to begin with. They give you something good with one hand, slap you in the face with the other. The 15" already has a lot of power user advantages over the 13", they could of at least given the 13" 4 'proper' TB3 ports.
    Yes, because of course, we all know that 'everyone' who buys the 13" will fully saturate all four ports simultaneously playing Tetris on their twin 5k monitors and saving their Facebook output to raid 3 arrays.
    Bad Apple
    stantheman2old4funiqatedostevehtmaymagman1979randominternetpersonDeelronindyfxai46
  • Reply 9 of 86
    The comment section shows that the author of the article has not made the cause for the issue clear enough.

    Processors today use PCIe to connect everything from Storage controllers, high speed I/O like USB, Thunderbolt and other stuff including SD-Card readers and Graphic Cards (or discrete GPU in case of macbook). And on each processor model there is only a specific number of these lanes available. This means that since Apple has to rely on Intel on this issue, they can't simply change this behavior by putting in a second controller, it's simply not possible because there is no dual core i7 Chip with enough lanes. Thats why Apple has chosen to use the PCH-supplied PCIe-Lanes.

    PCH is an additional chip (which is integrated directly in the processor package on some models) which connects to the processor via a seperate high speed bus and it gives you many things included USB, keyboard support, audio and storage interface and additional (about half speed) PCIe-Lanes in one single chip. What I think is the case is that Apple is using these lanes because the processor itself does not supply enough PCIe-lanes.

    So obviously, there is nothing to be added from a non-technical viewpoint, because it's not about power consumption or other marketing decisions, it's simply because Intel does not make the chips Apple needs for four Thunderbolt 3 full speed capable ports.
    edited October 2016 BraddsUKJanNL2old4funstevehmazda 3stmayPolyphonielmagoothewhitefalcondysamoria
  • Reply 10 of 86
    The comment section shows that the author of the article has not made the cause for the issue clear enough.

    Processors today use PCIe to connect everything from Storage controllers, high speed I/O like USB, Thunderbolt and other stuff including SD-Card readers and Graphic Cards (or discrete GPU in case of macbook). And on each processor model there is only a specific number of these lanes available. This means that since Apple has to rely on Intel on this issue, they can't simply change this behavior by putting in a second controller, it's simply not possible because there is no dual core i7 Chip with enough lanes. Thats why Apple has chosen to use the PCH-supplied PCIe-Lanes.

    PCH is an additional chip (which is integrated directly in the processor package on some models) which connects to the processor via a seperate high speed bus and it gives you many things included USB, keyboard support, audio and storage interface and additional (about half speed) PCIe-Lanes in one single chip. What I think is the case is that Apple is using these lanes because the processor itself does not supply enough PCIe-lanes.

    So obviously, there is nothing to be added from a non-technical viewpoint, because it's not about power consumption or other marketing decisions, it's simply because Intel does not make the chips Apple needs for four Thunderbolt 3 full speed capable ports.
    Still, most of the time Apple will not bow down to restrictions others set. If they felt the need to offer four fast ports they would have made it happen. So apparently Apple does not feel the need. I do, I think this machine is somewhat crippled by this design choice. Apple is not earning many sympathy points from me on this one. 
    singularitydysamoriaentropysawesomeepicguyDonvermoaylk
  • Reply 11 of 86
    Apple should have equipped the 13" model with quad-core CPUs. How can anyone call a dual-core laptop Pro? It's like selling a sports car with a 50 HP engine.

    Current 13" prices would start making sense if these MacBook Pro models had quad-core CPUs and twice the amount of RAM. 

    The only model with a dual-core CPUs should have been the one without the Touch Bar, and in its basic configuration it should have been $1199. 
    edited October 2016 chelindysamoriaperkedelentropysbaconstangDonvermotofinoavon b7
  • Reply 12 of 86
    The comment section shows that the author of the article has not made the cause for the issue clear enough.

    Processors today use PCIe to connect everything from Storage controllers, high speed I/O like USB, Thunderbolt and other stuff including SD-Card readers and Graphic Cards (or discrete GPU in case of macbook). And on each processor model there is only a specific number of these lanes available. This means that since Apple has to rely on Intel on this issue, they can't simply change this behavior by putting in a second controller, it's simply not possible because there is no dual core i7 Chip with enough lanes. Thats why Apple has chosen to use the PCH-supplied PCIe-Lanes.

    PCH is an additional chip (which is integrated directly in the processor package on some models) which connects to the processor via a seperate high speed bus and it gives you many things included USB, keyboard support, audio and storage interface and additional (about half speed) PCIe-Lanes in one single chip. What I think is the case is that Apple is using these lanes because the processor itself does not supply enough PCIe-lanes.

    So obviously, there is nothing to be added from a non-technical viewpoint, because it's not about power consumption or other marketing decisions, it's simply because Intel does not make the chips Apple needs for four Thunderbolt 3 full speed capable ports.
    I have absolutely no technical knowledge on the subject, but the article says the low-power Intel processors provide full bandwidth on all 4 ports on the 13" Pro without Touch Bar. If there is a technical reason for reduced bandwidth on the two right ports of the 13" Pro (as opposed to it being an economy measure), it seems more like the Touch Bar is responsible. Perhaps it absorbs (uses) some of the PCIe-Lanes you describe.
    longpath
  • Reply 13 of 86
    misamisa Posts: 827member
    1983 said:
    Why? Here we go again Apple crippling the 13" Pro's spec in comparison to the ridiculously more expensive 15" version. Even though they're both very expensive laptops to begin with. They give you something good with one hand, slap you in the face with the other. The 15" already has a lot of power user advantages over the 13", they could of at least given the 13" 4 'proper' TB3 ports.
    I'm almost willing to bet this is a limitation of the CPU. The 15" models are quad-cores while the 13" are dual-core. Notice there is also a RAM speed difference between 13" models as well that wouldn't otherwise be justified.

    What I bet, is that all 4 ports support full speed, but the dual core CPU doesn't have enough PCIe lanes to support running all of them on the dual core, so there's a bridge chip that creates more lanes, but is technically splitting one.

    If you look at https://thunderbolttechnology.net/sites/all/themes/tb/images/Thunderbolt3_infographic_100715.jpg

    You'll note that the chip itself is 10Gbits, and allows 4 PCIe lanes to go over thunderbolt. So to have 4 ports you need 16 PCIe lanes free. Take note that Skylake only has 16 PCIe lanes from the CPU, and 20 come from the PCH. Now, on the Quadcore models, you also have a dedicated GPU. That means those 16 lanes on the CPU are connected to the GPU, and all the thunderbolt lanes are connected to the PCH. 

    So if you look at http://ark.intel.com/products/91169/Intel-Core-i7-6660U-Processor-4M-Cache-up-to-3_40-GHz , which is a dual core, what do you see?
    12 PCIe lanes.

    Versus the top-of-the-line model http://ark.intel.com/products/93336/Intel-Core-i7-6970HQ-Processor-8M-Cache-up-to-3_70-GHz
    16 PCIe lanes.

    So if this is the kind of thing Apple did, then it's reasonable to believe that the 13" model only has 12 PCIe lanes, so two ports are going to share 4 lanes. That may not be meaningful depending on what you connect to it. Desktop and Server models all have 16 PCIe lanes.

    Some dual core models only have 10 lanes (m5 and m7 models.) 


    mazda 3stmaydysamoriamagman1979kpomDeelronration al
  • Reply 14 of 86
    sandorsandor Posts: 549member
    and you cannot get the (finally available) 2 TB SSD upgrade on the 13"

    the purpose of a portable is to be portable. some professionals don't want to travel with a 15"
    Apple needs a 13" *real* pro that can be a smaller, spec-maxed computer.

  • Reply 15 of 86
    The comment section shows that the author of the article has not made the cause for the issue clear enough.

    Processors today use PCIe to connect everything from Storage controllers, high speed I/O like USB, Thunderbolt and other stuff including SD-Card readers and Graphic Cards (or discrete GPU in case of macbook). And on each processor model there is only a specific number of these lanes available. This means that since Apple has to rely on Intel on this issue, they can't simply change this behavior by putting in a second controller, it's simply not possible because there is no dual core i7 Chip with enough lanes. Thats why Apple has chosen to use the PCH-supplied PCIe-Lanes.

    PCH is an additional chip (which is integrated directly in the processor package on some models) which connects to the processor via a seperate high speed bus and it gives you many things included USB, keyboard support, audio and storage interface and additional (about half speed) PCIe-Lanes in one single chip. What I think is the case is that Apple is using these lanes because the processor itself does not supply enough PCIe-lanes.

    So obviously, there is nothing to be added from a non-technical viewpoint, because it's not about power consumption or other marketing decisions, it's simply because Intel does not make the chips Apple needs for four Thunderbolt 3 full speed capable ports.
    I have absolutely no technical knowledge on the subject, but the article says the low-power Intel processors provide full bandwidth on all 4 ports on the 13" Pro without Touch Bar. If there is a technical reason for reduced bandwidth on the two right ports of the 13" Pro (as opposed to it being an economy measure), it seems more like the Touch Bar is responsible. Perhaps it absorbs (uses) some of the PCIe-Lanes you describe.
    The 13" without Touch Bar only has 2 ports. 
    randominternetpersonindyfxration al
  • Reply 16 of 86
    The comment section shows that the author of the article has not made the cause for the issue clear enough.

    Processors today use PCIe to connect everything from Storage controllers, high speed I/O like USB, Thunderbolt and other stuff including SD-Card readers and Graphic Cards (or discrete GPU in case of macbook). And on each processor model there is only a specific number of these lanes available. This means that since Apple has to rely on Intel on this issue, they can't simply change this behavior by putting in a second controller, it's simply not possible because there is no dual core i7 Chip with enough lanes. Thats why Apple has chosen to use the PCH-supplied PCIe-Lanes.

    PCH is an additional chip (which is integrated directly in the processor package on some models) which connects to the processor via a seperate high speed bus and it gives you many things included USB, keyboard support, audio and storage interface and additional (about half speed) PCIe-Lanes in one single chip. What I think is the case is that Apple is using these lanes because the processor itself does not supply enough PCIe-lanes.

    So obviously, there is nothing to be added from a non-technical viewpoint, because it's not about power consumption or other marketing decisions, it's simply because Intel does not make the chips Apple needs for four Thunderbolt 3 full speed capable ports.
    I have absolutely no technical knowledge on the subject, but the article says the low-power Intel processors provide full bandwidth on all 4 ports on the 13" Pro without Touch Bar. If there is a technical reason for reduced bandwidth on the two right ports of the 13" Pro (as opposed to it being an economy measure), it seems more like the Touch Bar is responsible. Perhaps it absorbs (uses) some of the PCIe-Lanes you describe.

    They provide full bandwidth on all ports yes, but the 13" Pro without Touch Bar only has 2 thunderbolt ports.
    edited October 2016 kpomindyfxlongpath
  • Reply 17 of 86

    sandor said:
    and you cannot get the (finally available) 2 TB SSD upgrade on the 13"

    the purpose of a portable is to be portable. some professionals don't want to travel with a 15"
    Apple needs a 13" *real* pro that can be a smaller, spec-maxed computer.


    New 15" Pro is only marginally bigger and heavier than MBA. 
    jlanddindyfxtofino
  • Reply 18 of 86
    13" 4 port:

    2 ea 40Gb/s Thunderbolt (TB3)
    2 ea 20Gb/s Thunderbolt, but still the TB3 spec

    That's really cool.  

    randominternetpersonkpomindyfxstevehentropyswatto_cobra
  • Reply 19 of 86
    Mike WuertheleMike Wuerthele Posts: 4,880administrator
    The comment section shows that the author of the article has not made the cause for the issue clear enough.

    Processors today use PCIe to connect everything from Storage controllers, high speed I/O like USB, Thunderbolt and other stuff including SD-Card readers and Graphic Cards (or discrete GPU in case of macbook). And on each processor model there is only a specific number of these lanes available. This means that since Apple has to rely on Intel on this issue, they can't simply change this behavior by putting in a second controller, it's simply not possible because there is no dual core i7 Chip with enough lanes. Thats why Apple has chosen to use the PCH-supplied PCIe-Lanes.

    PCH is an additional chip (which is integrated directly in the processor package on some models) which connects to the processor via a seperate high speed bus and it gives you many things included USB, keyboard support, audio and storage interface and additional (about half speed) PCIe-Lanes in one single chip. What I think is the case is that Apple is using these lanes because the processor itself does not supply enough PCIe-lanes.

    So obviously, there is nothing to be added from a non-technical viewpoint, because it's not about power consumption or other marketing decisions, it's simply because Intel does not make the chips Apple needs for four Thunderbolt 3 full speed capable ports.
    I have absolutely no technical knowledge on the subject, but the article says the low-power Intel processors provide full bandwidth on all 4 ports on the 13" Pro without Touch Bar. If there is a technical reason for reduced bandwidth on the two right ports of the 13" Pro (as opposed to it being an economy measure), it seems more like the Touch Bar is responsible. Perhaps it absorbs (uses) some of the PCIe-Lanes you describe.
    The 13-inch without the Touch Bar has only two Thunderbolt 3 ports, not 4.
    Soliindyfx
  • Reply 20 of 86
    stevehsteveh Posts: 480member
    I have absolutely no technical knowledge on the subject, but the article says the low-power Intel processors provide full bandwidth on all 4 ports on the 13" Pro without Touch Bar. If there is a technical reason for reduced bandwidth on the two right ports of the 13" Pro (as opposed to it being an economy measure), it seems more like the Touch Bar is responsible. Perhaps it absorbs (uses) some of the PCIe-Lanes you describe.
    If the article says the MBP without Touchbar has four USB-C ports, it's wrong.

    The base 13" MBP has two USB-C ports.
    Solikpomindyfx
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