Ram slot configuration

Discussion in 'Mac Pro' started by IanK MacPro, Oct 12, 2018.

  1. IanK MacPro, Oct 12, 2018
    Last edited: Oct 12, 2018

    IanK MacPro macrumors member

    Joined:
    Jul 6, 2018
    Location:
    Buckinghamshire, UK
    #1
    Hi Everyone, I'm just about to upgrade the ram on my 3x MacPro 4.1>5.1's, all 12-core 3.46.

    2 of the machines are running dual 1080ti's for redshift rendering and could do with a bit more ram.

    They all currently have 32GB (8x 4gb) and I'm about to purchase an extra 4x 16gb for each machine which will leave me with the potential to upgrade to more if needed in the future.

    With 4x 16gb installed, will I be ok filling the remaining empty slots with 4x 4gb or will there be any issues?

    Also if I do go this route, what would be the best slot configuration for a mix of 4x 16gb & 4x 4gb?

    Any help greatly appreciated!
     
  2. expede macrumors regular

    expede

    Joined:
    Jan 15, 2018
    Location:
    Sweden
  3. IanK MacPro thread starter macrumors member

    Joined:
    Jul 6, 2018
    Location:
    Buckinghamshire, UK
    #3
    Thanks but that is assuming all equal sized DIMMs
     
  4. expede macrumors regular

    expede

    Joined:
    Jan 15, 2018
    Location:
    Sweden
    #4
    [​IMG]
    This means that you first you put the 16GB in slot 1,2,5,6 and the rest 4GB in the rest
    /Per
     
  5. h9826790, Oct 13, 2018
    Last edited: Oct 14, 2018

    h9826790 macrumors G5

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #5
    Don’t worry about the difference in capacity. If they are not in optimum config, the OS will tell you once boot to desktop, just copy the recommended config, then shut down, and re-arrange your DIMM.

    However, you have to worry more about if your current DIMM are RDIMM. Your 16GB DIMM should be RDIMM, if your current 4GB DIMM are UDIMM, then they cannot be used together.
     
  6. tsialex macrumors 601

    tsialex

    Joined:
    Jun 13, 2016
    Location:
    Brazil
    #6
    The best way is to put the same amount of RAM to each processor, so one don't need to use NUMA so much. The best way is to put 2 16GB DIMMs and 2 4GB DIMMs for each processor.
     
  7. IanK MacPro thread starter macrumors member

    Joined:
    Jul 6, 2018
    Location:
    Buckinghamshire, UK
    #7
    Thanks for your help guys ill make sure I check if my current DIMMS are RDIMM or UDIMM first, all being well ill split the DIMMS evenly between the 2 processors.
     
  8. IanK MacPro thread starter macrumors member

    Joined:
    Jul 6, 2018
    Location:
    Buckinghamshire, UK
    #8
    Received the 16gb DIMMS today, all works fine in the following configuration:

    Slot1: 16gb Slot2: 16gb
    Slot3: 4gb Slot4: 4gb

    Slot5: 16gb Slot6: 16gb
    Slot7: 4gb Slot8: 4gb

    Total: 80Gb

    My old 4gb DIMMS all had heat spreaders on them, is it worth transferring these over to the new 16Gb modules?

    memory.jpg
     
  9. tsialex macrumors 601

    tsialex

    Joined:
    Jun 13, 2016
    Location:
    Brazil
    #9
    Check your RAM temperatures with iStat or another app, if the new ones are hotter that the old ones, do the heat spreader swap.

    Test your new memory a lot before doing that, you probably will loose your warranty. I usually only do the heat spreader install after the warranty/return window expires.
     
  10. IanK MacPro thread starter macrumors member

    Joined:
    Jul 6, 2018
    Location:
    Buckinghamshire, UK
    #10
    Great, will do. Thanks for the advice
     
  11. Zeke D macrumors 65816

    Zeke D

    Joined:
    Nov 18, 2011
    Location:
    Arizona
    #11
    Only slightly off topic.
    I my 2010, I had followed the manual with four identical 4GB ECC dimms, and placed them in slots 1,2 & 5,6. I tossed in a Lion install, and the memory slot utility popped up and suggested that I put them in slots 2,3 & 6,7.

    I moved the DIMMs, and saw no performance decrease running Sierra. Any ideas why the memory slot utility suggested a configuration contrary to the manual?
     
  12. h9826790 macrumors G5

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #12
    No idea, but that won't make any difference anyway, each DIMM still has their own channel.

    IMO, just follow the memory slot utility's suggestion can't go wrong. It's definitely more update than the original manual, and it's directly from Apple.
     

Share This Page

11 October 12, 2018