Resolved Mac Pro 4,1 Backplane PCIe Booster Power Issues

Discussion in 'Mac Pro' started by tnthlmnt, Jul 7, 2018.

  1. tnthlmnt macrumors newbie

    Joined:
    Sep 6, 2017
    #1
    Hi!

    Couldn't find anything like this in a few searches here or on Google. Just flashed an EVGA GTX 680 (using the guide found on this site, THANKS!) and everything works great except it doesn't look like it is pulling power from both 6 pin connectors on the logic board. iStat shows PCIe Boost B with an fluctuating amperage draw based on load but PCIe Boost A shows a flatline reading of 0ma. Is this something to be concerned about or is iStat just not reporting info correctly?

    Benchmarks
    LuxMark 3.1 Ball - 5190
    Geekbench OpenCL - 51867
    Geekbench Metal - 66163

    Scores appear to be in the right ballpark and the system is stable, just wondering if anyone else has stumbled across something similar to what I'm experiencing.

    Thanks!
     
  2. h9826790 macrumors G4

    h9826790

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    #2
    Any screen capture?

    If no power from one of the 6pin, the card shouldn’t able to work normally, especially under high stress. If you can run benchmarks, there should be no powering issue.

    However, it’s hard to know why you have that kind of reading.
     
  3. tnthlmnt thread starter macrumors newbie

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    Sep 6, 2017
    #3
    Thanks for the reply!

    I've attached a few screenshots showing some iStat readouts focusing on PCIe Boost A and B. I also have a system profiler screenshot showing what I think is a successfully flashed GTX 680. Thanks again for taking the time to read this!

    iStat PCIe Boost A.png iStat PCIe Boost B.png System Profiler PCI.png
     
  4. tsialex macrumors 65816

    tsialex

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    Jun 13, 2016
    #4
    Stupid question, but did you tried to invert the PCIe 6-pin cables on the GPU and checked with the lines on iStat inverted too? If so, maybe you have a problem on a cable or on the GPU power plane/power connector.

    Seems flashed correctly, I think that's the same as my original eVGA GTX680 for Mac.
     
  5. h9826790 macrumors G4

    h9826790

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    #5
    I agree the first thing to do is swap the mini 6pins, and check if any reading changes.
     
  6. tnthlmnt thread starter macrumors newbie

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    Sep 6, 2017
    #6
    Thanks guys, just swapped the mini 6 pins and the reading in iStat stays the same. I uninstalled and reinstalled iStat and it's still giving the same 0ma reading for PCIe Boost A. Everything appears to be working correctly other than that reading.
     
  7. VanneDC macrumors 6502a

    VanneDC

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    #7
    Can U go into windows and take a look at gpuZ or CpuZ , I don't trust istat. Or another monitor program on OSX?
     
  8. h9826790 macrumors G4

    h9826790

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    #8
    No software in Windows can tell the mini 6pin’s reading.

    But yes, in Windows, GPU-Z should able to tell the card’s total power draw. As long as that’s normal, which means the mini 6pins are working.
     
  9. tnthlmnt thread starter macrumors newbie

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    Sep 6, 2017
    #9
    What other OS X monitoring software would you recommend? I don't currently have Windows on my machine but I'm hoping to install a copy soon. Thanks for all the help and ideas so far!
     
  10. macagain macrumors regular

    macagain

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    #10
    Mine (flashed PNY reference GTX680) does show power draw from both connectors.
     

    Attached Files:

  11. tnthlmnt thread starter macrumors newbie

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    #11
    Looks like the problem might be related to the software? I just swapped my RX 580 back in to see if the problem went away and now iStat is still showing PCIe Boost A with a 0ma reading. I'm using a dual mini 6 pin to single 8 pin cable to power the RX 580. I've sent some log files to iStat to see what they can find out. Everything appears to be fine, just feels extremely weird seeing that 0ma value. Will post back if I hear anything!
     
  12. VanneDC macrumors 6502a

    VanneDC

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    #12
    might just be as simple as the voltage monitor on that 6pin slot pushing up daisies.
     
  13. tnthlmnt thread starter macrumors newbie

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    Sep 6, 2017
    #13
    I was able to switch out the back plane and the problem is now gone. Looks like it could be the voltage monitor on that 6 pin connector that is no longer reporting values. Thanks for all the thoughts ideas and input on this!
     
  14. crjackson2134 macrumors 68040

    crjackson2134

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    #14
    Sorry if this is off topic, but how hard was it to change the backplane board?

    Lightning struck my house a few months ago, and crippled one of my ethernet ports. It’s now 100BASE-T instead of 1000BASE-T.
     
  15. tnthlmnt thread starter macrumors newbie

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    #15
    It was a big enough job, probably took half an hour to carefully take everything apart and then another half hour to put it all back. You take out almost everything in the tower to get to it. You can leave the power supply where it is... If you are familiar with working on computers (cautious of static electricity etc.) and have the right tools it’s definitely doable. The fan and speaker connectors for the processor cage were my least favourite part of the job. Hope that helps!
     
  16. crjackson2134 macrumors 68040

    crjackson2134

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    #16
    Thanks... It does help.

    I’ve built a couple of hundred PC’s from scratch, but have very little hands-on with the innards of my cMP.

    I’m not sure it’s worth the effort in my case, but I may eventually take that route. I actually have fought with the fan and speaker connections before. I had it pulled apart for a thorough cleaning, and a BT/WiFi upgrade.

    This was the main reason for my question. After that cleaning job, I wondered if it might be biting off more than I want.
     
  17. Synchro3, Jul 14, 2018
    Last edited: Jul 14, 2018

    Synchro3 macrumors 68000

    Synchro3

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    #17
    I just did that, it isn't difficult if you use the Technician Guide: https://forums.macrumors.com/threads/mac-pro-5-1-no-boot-up-black-screen.2124447/#post-26201323

    Mac Pro Technician Guide: Mac Pro (Mid 2010) - tim.id.au

    - Pull out optical drive carrier (page 132)
    - Pull out hard drives
    - Pull out the Prozessor tray (page 135)
    - Pull out all PCI cards
    - Pull out the PCI fan (page 142)
    - Remove a cover to to gain access to the MoBo power connector (page 150/151)
    - Remove processor cage (page 165)
    - Remove some cables (page 200 and following)
    - Remove backplane board (page 202 and following)


    Regarding upgraded Mac Pro 4,1 with 5,1 firmware with W3680/3690/X5680/5690 CPU:

    The new backplane board must be a Mac Pro 4,1 board:
    - Install the old CPU (lucky if you didn't sell it)
    - Upgrade to the latest 4,1 firmware
    - Upgrade to 5,1 firmware (Netkas forum)
    - Install the new CPU
     
  18. crjackson2134 macrumors 68040

    crjackson2134

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    #18
  19. h9826790 macrumors G4

    h9826790

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    #19
    Yes, the new logic board will come with a new serial number.

    Identity should not be changed, because you MUST get the correct logic board. If your cMP is the 2009, you must get the 2009 logic board. If your cMP is the 2010-2012 model, then must get the 2010-2012 logic board.

    If you already flashed your 4,1 to 5,1, and upgrade the CPU. Then you MUST downgrade the CPU back to something the 4,1 can boot. Then flash the new logic board to 5,1 again. And then re-upgrade the CPU again.
     
  20. crjackson2134 macrumors 68040

    crjackson2134

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    #20
    Mine is a 2013 produced 5,1 purchased new. Will the different SN affect anything like, Find My Mac, Back to my Mac, imessages, etc... ?

    Also, isn't there some kind of SN software one can use to change the SN back to original?
     
  21. h9826790 macrumors G4

    h9826790

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    #21
    I personally don't suggest anyone to do that. In fact, you can now dump your 5,1 firmware, and then flash it to the "new" logic board, then the new logic board should has the old S/N.

    Anyway, S/N shouldn't affect any functions, AFAIK, they are all base on your Apple ID. I changed my logic board few months ago, zero issue.
     
  22. crjackson2134 macrumors 68040

    crjackson2134

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    #22
    Perfect! When I tackle the task, I'll give this a go...
     
  23. Synchro3, Jul 14, 2018
    Last edited: Jul 27, 2018

    Synchro3 macrumors 68000

    Synchro3

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    Jan 12, 2014
    #23
    No, it doesn't affect anything above. For Apple you will just have a new Mac Pro, and you will get the message about new Mac registration on your i-Devices.

    For Apple I have now two Mac Pro's ;): https://getsupport.apple.com -> 'Show your products' and log in.

    Important is like h9826790 mentioned:
     
  24. tsialex, Jul 14, 2018
    Last edited: Jul 14, 2018

    tsialex macrumors 65816

    tsialex

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    Jun 13, 2016
    #24
    AFAIK, this will get you in trouble, maybe @LightBulbFun can correct me, but I think thats more or less this.

    The Mac Pro BootROM has 3 identifying infos, 2 unique:

    1) unique System Serial Number = SSN
    2) unique Logic Board Serial = LBS
    3) Model Order number i.e the SKU of your Mac

    With these three infos and your Ethernet Mac Addresses, Apple create the UUID for iMessage/FaceTime/iCloud.

    When you exchange your old board for a new one with Apple, the new board don't have a SSN but have LBS and Mac Addresses, so iMessage/FaceTime/iCloud works after you add your Mac serial number with Blank Board Serializer. That LBS + Mac Addresses was not yet associated with a Mac on Apple records for iMessage/FaceTime/iCloud and works ok with your previous SSN.

    When you change your original logic board to "new used" and put back your previous BootROM dump, Apple will reject your Mac on iMessage/FaceTime/iCloud since the LBS differ from the Mac Addresses. That's one way to identify a rouge cloning your Mac Pro or a hackintosh.
     
  25. LightBulbFun macrumors 68000

    LightBulbFun

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    London UK
    #25
    if you are fitting a new logic-board then yeah I recommend you fire up blank board serialiser and input your Mac Pros Serial number this is how Apple does it

    but this is assume you actually get an actually NEW logic-board/back plane

    if you have a used back plane but want to retain your Serial number etc then it SHOULD be possible to boot the Mac Pro from a clean install of OS X keep it off the internet and flash your old Mac Pros BootROM to the new board once this is done then you can continue to use the machine as normal

    however keep in mind im not exactly sure where the MAC addresses for the ethernet ports are stored in Mac Pro. and that this method wont work on newer machines due to those macs having intel mangment engine firmware which needs to be cleaned or moved over from the old ROM before hand
     

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