Pixlas 4.1 Mac Pro mod

Discussion in 'Mac Pro' started by AndreeOnline, Mar 26, 2015.

  1. Surrat macrumors 6502

    Surrat

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    #51
    Yes, you can do that. Or just use a cable splitter that ends in two 6-pins. Because the patch cable is directly connected to the PSU, it can easily handle running a splitter. Make sure to use 16guage wire, its thicker than the cheap cables have.
     
  2. AndreeOnline thread starter macrumors 6502

    AndreeOnline

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    Aug 15, 2014
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    Zürich
    #52
    I've updated my initial post again with links to the splice connector (Ebay auction for a bag of 25 connectors) and website for the cables (ModDIY). The cable was custom and cost $14 with free shipping from Hong Kong to Switzerland =)

    Please note the brown color of my connectors. They are specifically for 10-12 awg to 14-18 awg. My actual cables are 12 and 18 awg. It's important that you use the right connector.

    I think 16 awg is optimal for the custom cable down to the split. But the way my cable is designed I'm not sure if everything would fit in the first 8-pin.
     
  3. thornslack macrumors 6502

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    Nov 16, 2013
    #53
    Thanks for taking the initiative to try this out, and for documenting it so thoroughly! This is really very interesting, and opens up a number of intriguing possibilities. Congrats on your powerhouse machine, and looking forward to seeing your dual GPU results!
     
  4. m3rob macrumors member

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    Dec 28, 2010
    #54
    Thanks for the info. I need to find a dealer that supplies these splice connectors in the US. Can't wait to see your dual gnu results as well!

    Thanks again!
     
  5. AndreeOnline thread starter macrumors 6502

    AndreeOnline

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    #55
    I have saved a lot of time myself reading other peoples' threads, so it was an easy decision to try and share what I find.

    I pretty much know what dual gfx will give me. Bearfeats.com has many dual GPU tests and there's a dedicated DaVinci Resolve forum that I also found recently that has tested various rigs.

    I don't do games, so I'm not really into benchmarks and that kind of thing. Perhaps to check stability and such.

    But the recent updates to OS X are pushing dual GPU and if that trend continues it will be a nice option to have now that the CPUs are showing their age in single threaded apps.

    I've built a pretty specialized machine, but it fits my needs well!
     
  6. 666sheep macrumors 68040

    666sheep

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    #56
    This looks like a POS, but if it makes you happy it does not really matter, forum hero. ;) :p :D
     
  7. thornslack macrumors 6502

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    #57
    Didn't anyone ever tell you, if you can't say something nice, be quiet!
     
  8. AndreeOnline, Apr 17, 2015
    Last edited: Apr 19, 2015

    AndreeOnline thread starter macrumors 6502

    AndreeOnline

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    #58
    POS? Only in the sense Piece of slick:

    [​IMG]

    All is relative. With the protective plate in place you don't see any of it. The little plate doesn't fit 100%—let call it 85%, but it screws on and hides everything and allows the optical cage to glide in place normally.

    After that, all you have is a sleeved single cable that splits into two 8-pin. Not too shabby at all. Looks very clean. I would have preferred red cables instead of the yellow ones and a red sleeve that wasn't transparent, but communication with the cable makers wasn't easy at all times.

    At the end of the day, the goal was to come up with a mod that many would feel comfortable with, and I think this is doable for many "modders".

    That said—what is the point of your post? What can be read between the lines doesn't do you any credit.
     
  9. AndreeOnline thread starter macrumors 6502

    AndreeOnline

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    #59
    Updated with image showing the mod covered up as a finished install.
     
  10. Surrat macrumors 6502

    Surrat

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    #60
    Ignore the haters, your mod turned out great.
     
  11. 666sheep macrumors 68040

    666sheep

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    #61
    It's just my opinion and a bit of a joke (hence a bunch of emots at the end).
    What can be read between the lines depends on who's reading ;)
     
  12. mikeboss macrumors 65816

    mikeboss

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    switzerland
    #62
  13. AndreeOnline, Apr 20, 2015
    Last edited: Apr 20, 2015

    AndreeOnline thread starter macrumors 6502

    AndreeOnline

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    #63
    Cool! I was going to get back to them, but that doesn't seem to be necessary. :)

    And an additional note perhaps: I've measured 12.24V steady on all the 12V pins after the split and everything was stable running my 5870 and 280X in tandem. They aren't the hungriest cards, but it is all I can test right now.
     
  14. ActionableMango macrumors G3

    ActionableMango

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    Sep 21, 2010
    #64
    Nice work and thanks so much for sharing. This thread is a valuable addition to the forum.
     
  15. mikeboss macrumors 65816

    mikeboss

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    switzerland
    #65
    today the cables from hong-kong have arrived. I received the clips last week already. I finished the modification about half an hour ago and everything works as expected. no more need for "Macs Fan Control" :cool: all the internal fans of my Mac Pro are now behaving nicely and the graphics card(s) could literally pull hundreds of watts... I didn't even bother to re-attach the back plate in the optical drive compartment.
     
  16. AndreeOnline thread starter macrumors 6502

    AndreeOnline

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    #66
    Really great to hear! Cheers!
     
  17. Surrat macrumors 6502

    Surrat

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    #67
    Sounds great, my mod is still working perfectly. No problems or hiccups of any kind.
     
  18. zebity macrumors member

    Joined:
    Aug 1, 2008
    Location:
    Australia
    #68
    Thank you

    Thanks for very informative thread. I have just upgraded my Mac Pro 5,1 to dual 3.46 and have old power hungry Titan installed. The power mod will greatly help me as I have had power cut out a few times ....
    Ordered new cables and looking forward to smooth running.
    I might even add Titan X for dual CUDA grunt.

    Cheers,

    Zebity.
     
  19. s.m.t., Jun 22, 2015
    Last edited: Jun 22, 2015

    s.m.t. macrumors regular

    s.m.t.

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    #69
  20. benjaprud, Jun 23, 2015
    Last edited: Jul 12, 2015

    benjaprud macrumors member

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    #70
    My 4 drive sleds are in use. There's only one way to route the cable from the PSU to the PCI stage which is where the SATA cables goes from the logic board to the ODD, behind the protection plate. I used two 45cm PCIe extender cables (like the one on your second link) which connect together behind the plate. I didn't plan to use two cables, I just realized after receiving the first one that it was way too short, you need roughly 80cm of cable to go from the GPU to inside the PSU (it might vary slightly with the length of your graphics card and the path you choose). The hole was too small for the PCIe connector to go through so I had to remove the CPU tray, CPU cage and logic board to install the lower cable through the hole, under the logic board. Finally using two cables is a good thing because it allows me to disassemble the PSU without having to remove all the wiring (which would imply removing the logic board again).

    If you're worried about the power consumption of drives adding up close to the limit, drives don't draw that much current compared to CPU/GPU and 980W leaves a lot of room (especially on a single-CPU MP). If you want to convince yourself, watch the power consumption of your mac at full load on the "PSU, 12V" sensor using Hardware Monitor or iStat Menus. On my MP (1 CPU @ full load, Titan X @ full load, 4HDD spinning + 1SSD) I hit about 36A maximum, the PSU being rated for 79A. I could run two Mac Pros on the same PSU.

    Following the mod, with the GPU at full load with overclocking (TDP 110%, 275W) the PSU/PCI fan speeds went down from 1500/2250rpm to 925/1550rpm, my MP is now silent enough while gaming.

    EDIT : Here are some pics of my finished mod. I didn't quite cut each wire to the right length (which anyway would have been difficult) but I'm OK with the result :

    [​IMG]

    [​IMG]
     
  21. s.m.t. macrumors regular

    s.m.t.

    Joined:
    Mar 7, 2010
    #71
    My intention is to take 8 cables soldered to the PSU with an 8 pin PCI-E connection, then run another 8 cables down to the graphics card, at the end of which splits into two 6+2 PCI-E connections.

    My concern at this point is if those 8 (18guage) conductors and PCI-E connectors can handle the load. Finding 16 guage cables seems to be a little harder to find. And then there is load rating of these 8 pin PCI-E connectors.

    Trying to future proof the design given the amount of work involved. If I was two run two cards that require one 8 pin and 1 6 pin, I use this cable from the PSU to power the 8 pin for each card; then use the two 6 pin connections off the main board to power the 6 pin connection on each card.

    Or worst case, the cable from the PSU could power one card that requires two 8 pin connections.

    The total power draw could be large in either case...
     
  22. zebity, Jun 23, 2015
    Last edited: Jun 26, 2015

    zebity macrumors member

    Joined:
    Aug 1, 2008
    Location:
    Australia
    #72
    Power Mod'ers,

    after long wait for various parts I have completed variation of Andree mod.

    I did the following:

    1. Got a PCI-e extension cable and clipped one end off and soldered to backside of power supply 12V & GND pins
    2. Feed the PCI-e extension out from power supply (as per the existing twelve strand cable)
    3. Fed ModDIY cable (as per Andree) up into optical drive bay
    4. Using Molex crimping tool added female PCI-e connector to ModDIY cable
    5. Simply plugged PCE-e extension tail into new PCI-e cable that feeds down into card bay

    This seemed like a simple approach as I wanted to avoid soldering if possible, but having never used Molex crimper before I quickly learnt this getting crimps right is a bit if an art... I used 17 pins to get 8 correct crimps and also had problems with having to remove pins from connector when testing proved that connection was not working within the Molex join.

    This added to cost, as I purchased Crimper and Removing tools.

    Also to get solder to join on underside of power supply board, I had to use Dremel tool to drill out cavity to get surface that would bind ok (just using flux did not help).

    Here are some picture of results:

    IMG_2626.JPG IMG_2658.JPG IMG_2659.JPG IMG_2669.JPG IMG_2670.JPG


    Many thanks to Andree for detailed info on how to do this.

    NOTE: that I have yellow wires going to GND terminals, as this is how the PCI-e extension was wired, which is opposite of modDIY cable...

    NOTE 2: While internals of power supply are all clearly labeled I still tested everything with volt meter before plugging into my Nvidia Titan card.

    Cheers,

    Zebity
    (Mac Pro (2012) with 2 x 3.46GHz + Areca ARC-1883LP + Nvidia Titan)
     
  23. s.m.t., Jun 24, 2015
    Last edited: Jun 24, 2015

    s.m.t. macrumors regular

    s.m.t.

    Joined:
    Mar 7, 2010
    #73
    Looks good, just curious as to why you put the female connection on the PSU side? Is your PSU our of a 4,1 or a 5,1? Picture of the layout looks a little different than others have posted...

    I have my 980 Ti and cables ordered. Hopefully doing this mod myself this weekend.
     
  24. zebity macrumors member

    Joined:
    Aug 1, 2008
    Location:
    Australia
    #74
    SMT,


    I just followed plug type backwards from moddiy starting point.

    Moddiy: molex male -> (bare wire becomes) female (light blue plastic) , so
    Power supply bare wire -> male (black plastic).

    Where:
    male == plastic male with female internal pins
    Female == plastic female with male internal pins.

    This way moddiy is just male to female as per standard extension cable, and made it easy to ensure +ve went to +ve (yellows on moddiy) and -ve to -ve (blacks on Moddiy).

    Not sure if this is different to what you would do or if pictures make it hard to see.

    Yes I noticed my power supply pictures are different. My cMP is late 2012 (5,1). I got it direct from Apple very close to when apple stopped shipping cMPs, so I know it is guenuine late 2012 model.

    Good luck with mod.

    Cheers,

    Zebity.
     
  25. s.m.t., Jun 27, 2015
    Last edited: Jun 27, 2015

    s.m.t. macrumors regular

    s.m.t.

    Joined:
    Mar 7, 2010
    #75
    Ohh Ok, just curious... Makes sense the cable then is treated as an extension...

    My intent is a little different, wanted to wire it up so the PSU is like a traditional modular PSU and then I just use a cable like that which comes with that design PSU...

    Going to solder two separate cables in. From my research the molex pins are the bottleneck. 18 Gauge wire could handle the full potential of two 8pin PCI-E connections, 300W each (14.5A@12v). But depending on the quality of the pins/connectors used, each pin can be rated anywhere from 8-12 depending on if they are standard, HCS, or plus HCS connectors.
    http://www.tomshardware.com/reviews/power-supply-specifications-atx-reference,3061-12.html

    I found a thread somewhere that suggested all molex connectors made as of a certain date were mandated to be HCS or above... But not knowing for sure, I am going to play it safe and not do any doubling up or splitting... 3(12v)*8A=24A@12v=288W doesn't leave a lot of room for surge, but would probably be fine... That also assumes the card doesn't try and draw more than 8A from each conductor...

    [​IMG]
    I ordered this cable to wire into the PSU:
    http://www.newegg.com/Product/Product.aspx?Item=N82E16812162033
    Will cut off the female 6+2 connector and solder that to the PSU.

    Then the plan is to use this cable to connect to the graphics card:
    http://www.newegg.com/Product/Product.aspx?Item=N82E16812162021
     

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