Mac Pro 4,1 RAM speed question.

Discussion in 'Mac Pro' started by adam9c1, Feb 13, 2015.

  1. adam9c1 macrumors 68000

    adam9c1

    Joined:
    May 2, 2012
    Location:
    Chicagoland
    #1
    I have a Mac Pro 4,1 which is running DDR3 1066.

    Can I install DDR3 1600 which was removed from a 5,1?

    Thank you.
     
  2. Macsonic macrumors 65816

    Macsonic

    Joined:
    Sep 6, 2009
    Location:
    Earth
    #2
    The ram that came from the 5,1 Mac Pro, do you mean the ram is PC3-10600 DDR3 at 1333Mhz ? If it came from the 5,1 Mac Pro you can install the ram though if your processor is a quad core single socket or an 8 core dual socket, your 4,1 Mac Pro will read the ram as 1066Mhz speed and will work fine. If your processor is a 6 core, single socket, your Mac will read it at 1333Mhz.
     
  3. h9826790 macrumors G3

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #3
    Yes, the RAM should automatically downclock itself to run at 1066MHz.
     
  4. scotttnz macrumors 6502a

    Joined:
    Dec 16, 2012
    Location:
    Auckland, New Zealand
    #4
    I'm running 1866MHz RAM in my 4,1 because I had some handy when I got the Pro. It automatically clocked down to 1066MHz and has been running fine for 6 months or so. It should ramp up to 1333MHz when I eventually get around to dropping a 6 Core X5680 or X5690 into the box.
     
  5. mattspace macrumors 6502a

    mattspace

    Joined:
    Jun 5, 2013
    Location:
    Australia
    #5
    This is a question i was going to ask as well - so as a folowup, is the speed dependent on the processor or the firmware - ie is there any point to doing the 5.1 upgrade on a 4.1 with 1300 ram, if its still got the original cpus?
     
  6. h9826790 macrumors G3

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #6
    It depends on both. If you keep the old CPU, you won't get faster RAM regardless your firmware version.
     
  7. flowrider macrumors 601

    flowrider

    Joined:
    Nov 23, 2012
    #7
    Answers above.

    Lou
     
  8. adam9c1 thread starter macrumors 68000

    adam9c1

    Joined:
    May 2, 2012
    Location:
    Chicagoland
    #8
    Thank you all for the replies.

    I'll shut down the machine and install the ram tonight.
    uptime: 94 days. ;-)
     
  9. adam9c1 thread starter macrumors 68000

    adam9c1

    Joined:
    May 2, 2012
    Location:
    Chicagoland
    #9
    Installed the new memory in banks 1,2,5,6.

    System boots ok.
    If I mix the old memory in slots 3,4,7,8 no boot. Blinking front light.
    (Tried both sets of old memory)

    So I'm up from 16GB to 32GB now.
     
  10. flowrider macrumors 601

    flowrider

    Joined:
    Nov 23, 2012
    #10
    ^^^^Don't know, but as a guess, I would say your trying to mix buffered and unbuffered RAM. And you can't do that. Also is the new RAM ECC?

    Lou
     
  11. adam9c1 thread starter macrumors 68000

    adam9c1

    Joined:
    May 2, 2012
    Location:
    Chicagoland
    #11
    Old RAM

    HYNIX
    2GB 1Rx8 PC3L-10600R-9-10-A1
    HMT325R7BFR8A-H9 T7 AB 1140



    New RAM
    Patriot Viper
    4x8GB kit PC3-12800 1600MHz
     
  12. h9826790 macrumors G3

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #12
    You can't mix registered and unregistered RAM.
     

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