2013 MacPro: Thunderbolt on front or back?

Discussion in 'Mac Pro' started by JesterJJZ, Jul 2, 2012.

  1. JesterJJZ macrumors 68020


    Jul 21, 2004
    In an effort to talk about something new, where do you think the TB ports would be in a future Apple tower?

    If there are only two ports, both on the back or one back and one up front?

    If three or more ports I think one on the front and rest on back are a given.
  2. theSeb macrumors 604


    Aug 10, 2010
    Poole, England
    The new Mac Pro will be twice the size of the Mac Mini and have 6 Thunderbolt ports. Or not.

    I am expecting at least 2 Thunderbolt ports and I hope they don't make it thinner and smaller to go with Apple's current design philosophy and obsession with thin things. I like my women thin. Desktop computers? Not so much.
  3. JesterJJZ thread starter macrumors 68020


    Jul 21, 2004
    My main concern is the pci slots. TB isnt quite there to replace those.
  4. beaker7 macrumors 6502a

    Mar 16, 2009
  5. FrankHahn macrumors 6502a

    May 17, 2011
    At least two on the front and two on the back.
  6. -hh macrumors 68030


    Jul 17, 2001
    NJ Highlands, Earth
    The current configuration is:

    Two FireWire 800 ports
    Two USB 2.0 ports
    Front-panel headphone minijack and internal speaker

    Two FireWire 800 ports
    Three USB 2.0 ports
    Optical digital audio input and output TOSLINK ports
    Analog stereo line-level input and output minijacks

    Multichannel audio through Mini DisplayPort

    I suspect that FW800 will likely go away, at least on the front, with the next MP revision. A such, the front will probably be just a pair of USB3 ports and a headphone connection.

    For the back, a couple of TB ports, a couple more USB3 ports, and some audio connections (not sure if the analog is going to disappear quite yet).

    If Apple is aggresive, the FW800 ports on the back will go away too...particularly if there's a good aftermarket TB-FW adaptor. Ditto for one or both of the Gigabit Ethernet ports could go by the wayside too, in favor of putting all of the I/O eggs into the TB basket, although it is likely that if Apple were to do this, then a TB-Ethernet adaptor will probably come in the box.

    The net grand sum of this is that the minimalist extreme is to strip it down to just TB, although I don't really expect Apple to go that far in one jump...but then again, they've hinted at being at the 2013 change to be potentially radical.

    So while technically, I believe that all of the MP's external I/O interfaces could be able to be driven through use of an adaptor on a TB port (which may or may not presently exist), I do nevertheless expect that some ports will survive, with the most obvious ones being USB3 and audio connections as most likely, followed then by an "I hope" that Ethernet port and Firewire 800 ports also survive the next revision too, although I do really expect that the number of ports for each of these will get cut down.

  7. HurryKayne, Jul 2, 2012
    Last edited: Jul 2, 2012

    HurryKayne macrumors 6502a

    Jun 9, 2010
    Am i dreaming too much seeing a modular rackable ( as the rumor said) new desktop line?
    For example:
    entry level -->a mac mini 2013 ,quad core but no discrete gpu and one with
    second level-->if you choose the quad one without gpu you can add a second mini to go octo core or an external gpu (a mini chassis with a pci slot)
    third level-->Mini+2nd mini+Egpu chassis+ hard drive enclosure
    etc etc..
    So you basically can build your Mac..just like a pile.
  8. pprior macrumors 65816

    Aug 1, 2007
    i'm in no way an electronics engineer, but I believe that intel and others spend billions of dollars trying to find ways to get routes between devices efficient. I can't see any way of having major extra pathways between separate chasis efficient for example between CPUs or an "external" GPU - am I wrong here? The idea of a "stackable" sounds like a nice way of being able to customize, but what about multiple (small/noisy) cooling fans, connectivity issues, etc...

    and having everything via TB just moves the clutter to an external box, which is going to look like crap. Doing away with ethernet would be suicide, though FW I can see.
  9. CIA macrumors 6502a

    Jun 17, 2003
    Figure out what the next motherboard design will likely be (in terms of PCIe slots/lanes.) Look up the next Intel Xeon chips to be released next year and you will probably find details of the motherboard needed for them.

    Thunderbolt will be most likely cannibalizing lanes off the PCI bus for it's own use.

    You could guess the PCIe slots and Thunderbolt ports based on that.
  10. twietee macrumors 603


    Jan 24, 2012
    interesting thread, unless i'm missing something here, the one and only about the Next MP yet. Concerning the thread-title, I can imagine Thunderbolt on front and back.
    The sole question i was wondering about is if apple kills the optical drives entirely. Somehow unlikely in a professional device, but who knows. Would be strange having one in 2013 after a complete redesign, just to redesign it again 1,2,3 years later on to exclude it...no ODD would be THE major bummer imho.
  11. nanofrog macrumors G4

    May 6, 2008
    No guessing about it; it's the only way to connect a TB chip to the system.

    Now it's possible to use a PCIe switch, where lanes are shared on multiple ports, but this adds latency and ultimately reduces throughput if the lanes are in fact being used by more than one device simultaneously.

    This is what's currently done for slots 3 and 4, as there aren't enough lanes in Nehalem/Westmere to dedicate lanes to each slot as they're configured (electrical).

    SB gives a few more lanes, which will help, but the DP systems (80 lanes between both CPU's) are the only ones that would truly offer enough lanes to connect everything via dedicated lanes (no external PCIe switch required) with certainty, given the history of Intel based MP's (how the internal PCIe slots have been configured).

    SP systems running SB based Xeons could still require an external PCIe switch, depending on how they decide to configure the PCIe slots. Assuming such a system is delivered as we'd currently expect it in historical terms.
  12. All Taken, Jul 2, 2012
    Last edited: Jul 2, 2012

    All Taken macrumors 6502a

    Dec 28, 2009
    I could be wrong but i'm pretty sure thunderbolt connectors have a shorter distance than USB 3 placement wise away from the thunderbolt controller on the PCB. What I mean by this is if the trace back to the thunderbolt controller is longer than X then how would Apple place a daughterboard on the front for thunderbolt connectivity? I don't know if any manufacturer has a thunderbolt in case design?!?!?

    It might be interesting to see if another manufacturer has an existing or planned product similar to the Mac Pro you envisage.

    Edit: This is from anandtech -

    "As Thunderbolt carries more bandwidth than USB 3.0, trace routing is very important to achieving max performance. You'll notice that on all Thunderbolt boards we've tested thus far, the Cactus Ridge controller and Thunderbolt port are very close to one another. The spec for max trace length between the Thunderbolt controller and port is two inches, compared to up to 10 inches for Intel's USB 3.0 controller."

    Apple was a working partner on the lightpeak project but given the spec of two inches it might limit the thunderbolt connection on the front.
  13. deconstruct60 macrumors 604

    Mar 10, 2009
    Yes, this. The Thunderbolt controller has to be very close to the physical ports. That is likely going to be mean that there will just be at most two ports on the back. (if any at all.... it is still a "solution" in search of a core problem the Mac Pro doesn't have. )

    Probably the least disruptive way to do it would be to drop the two rear FW800 ports and replace them with Thunderbolt. Apple could leave two on the front for those who wedded FW without need of a dongle.

    Dropping Ethernet ports is loopy. If anything, Apple should be trying to move to 10GbE ports instead of dropping them. TB-> 1GbE are a tolerable kludge if necessary but on the Mac Pro that isn't even remotely creditable. The Mac Pro is 5U wide. You'd have to be on Apple crack to buy into the notion that "needed" to go to TB dongles for Ethernet to "save" width on Mac Pro. For "thinner than a inch" devices yes. For multiple inches thick devices .... it will be around for a long time.

    I would guess it would go like this (presuming adding TB )


    2 USB 3.0 (or maybe just one depend upon how many hubs they insert.)
    2 FW 800
    1 headphone jack + speaker.


    2 Thunderbolt ports
    2 USB 3.0 ports
    2 1GbE ports
    Optical digital audio input and output TOSLINK ports
    Analog stereo line-level input and output minijacks

    I expect Apple to dump USB 2.0 before they dump FW800 or Ethernet from the Mac Pro. I think they will generally avoid USB ports with color coded inserts to distinguish between 2.0 and 3.0 sockets. They just make them all 3.0. That will have a side effect of limiting the number of USB sockets. Those folks that need a bucketload of USB 2.0 ports will be pointed at TB expansion docks. Four is plenty especially in the context that most monitors have USB hubs in them.

    It shouldn't be too hard to move the FW controller to the front of the motherboard closer to the remaining sockets. It wasn't like there were multiple FW controllers in the Mac Pro anyway ( if I recall correctly. It was 4 sockets on the same controller, which actually has limitations.)

    While Intel has a new "more affordable" 10GbE motherboard controller now, I suspect Apple will not get it for a price they would like on this first iteration. It would be 'nice' if Apple helped move standard workstation networking to 10GbE. They are more likely to be tailing edge adopters there. (all the more so since 10GbE will somewhat compete for somewhat limited E5 1600 PCI-e lanes. )

    There are several designs. The issue is moving the Thunderbolt controller to the edge... not the draughtboards. The daughterboard is just the source of the PCI-e lanes. Those don't have a 2 inch limit. Largely because the bandwidth is broken down into more lanes PCI-e . Thunderbolt basically has two "lanes" going out and the path to the TB controller is 4 PCI-e lanes.

    The one quirk that Apple may run into with the daughterboard is that PCI-e v 3.0 is twice as fast as v2.0. The almost 90 degree turn the perpendicularly mounted daughterboard makes isn't so hot for the v3.0 signals any more than tend bends are unfriendly to TB controller to port connections.


    [ NOTE: the 8 USB 3.0 ports on the Intel board are really provided to two internal hubs that are connected to 2 USB 3.0 supply lines. Block diagram in the ]

    Toms hardware has another decent overview of some of the low level issues. ( namely how controllers bridge bandwidth )

  14. deconstruct60 macrumors 604

    Mar 10, 2009
    There are ways. They just are very affordable. Just about all of the top 10 supercomputers on the Top500 list are made up of multiple cabinets with very expensive "inter-cabinet" interconnect. That kind of networking tends to cost about as much as a Mac Pro to deploy. So pragmatically no. If splitting into multiple boxes means you almost double the cost it isn't worth doing. But if you have megabucks to blow ( as PCI-e links internal to a motherboard work just fine) you can. The supercomputer problem is that there are physically too many components to put onto one board. It has to be physically bigger to tackle ever larger problems.

    Some components are naturally coupled. (e.g., CPU and GPU ). Others are highly more options. (e.g., the need for 10 USB sockets vs. the need for 8 FW800 sockets ). The "modularize everything" folks go loopy trying to push customization past the resource/bandwidth couplings inherent in the components. Modular isn't always better.

    Another one of those natural couplings is between the TB controller and the GPU. With both of those embedded onto the motherboard a very straightforward natural solution is relatively easy. Separate those two and being the solution becomes more of a hack (non standard DisplayPort loop back connections ) or an outright kludge ( the ASUS optional TB card with video and control connectors ).
  15. nanofrog macrumors G4

    May 6, 2008
    As mentioned, trace routing is very important and tends to become more difficult as frequency is increased.

    RF/EMI, resistance, capacitance, and inductance for example all matter in trace routing. Too much interference, or undesirable electrical characteristics can cause signal integrity issues (unstable data transfers) that would limit it's performance, or worse, prevent it from working properly at all.

    But so long as the port can be placed near enough the TB chip, it's feasible. In the case of the MP, they'd need to place on the backplane board nearest the rear ports.

    Now as per this being necessary on a MP, strictly speaking, it isn't. In it's current form, it's aimed at the portable consumer market, which is why it was debuted in laptops rather than desktops.

    For simple sharing of devices between a laptop and desktop such as storage, all that's really needed is a data only TB card that plugs into a PCIe slot. I seem to recall at least one such product announcement, but haven't really looked to see if such a thing has actually materialized.

    This could even change for the enterprise market as well, so long as there are features added to TB to make it worth while. Such as creating an inexpensive high speed optical network for example. But this doesn't exist ATM.

    I agree. It would be an absolutely crazy thing to do.

    Unfortunately, I don't see this happening until Intel includes 10GbE on the chipset, going by all Intel based MP's released to date (increases margins).

    Also a foolish approach IMHO as well. It's not an iPad where the ability to add external ports is highly limited by the products' height (as well as power consumption and PCB real estate).

    Reasonable to me as well. Though it's possible that they would finally dump the FW800 chip as well in order to help offset the cost of the TB chip (keep in mind, the USB ports are located in the chipset, so there's no additional cost in terms of additional IC's).

    Assuming TB is actually included to begin with. :p
  16. ryan42 macrumors 6502


    Dec 3, 2003
    Near Houston, TX
    Not quite at all.

    PCIe 2.0 x16: 64Gbps
    Thunderbolt: 10Gbps
  17. beaker7 macrumors 6502a

    Mar 16, 2009
    Yep, and PCIe 3.0 ~128 Gbps
  18. ale500 macrumors regular

    Jul 9, 2007
    Do not forget that TB carries also video and thus some kind of special video card will be used. Are there any video cards with TB outputs on the market yet ?...
  19. OrangeSVTguy macrumors 601


    Sep 16, 2007
    Northeastern Ohio
    Has a few more lol.

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