Which RAM for Late 2015 5k iMac?

Discussion in 'iMac' started by jinyoungkim7, Jan 25, 2016.

  1. jinyoungkim7 macrumors regular


    Apr 14, 2010
    Maryland, USA
    To those of you who opted to get the Late 2015 5k iMac with 8gb and decided to upgrade the RAM themselves. Which RAM sticks did you buy and from where?
  2. Dksiazek macrumors newbie

    Mar 6, 2013
    Baltimore, MD
    Kingston Technology HyperX Impact Black 8GB 2133MHz DDR3L 1.35V Laptop Memory (HX321LS11IB2/8)

    Bought from Amazon, was only a few dollars more than the type that came with the computer. I have had no issues, and have just liked having the extra memory occasionally.
  3. dimme macrumors 65816

    Feb 14, 2007
    SF, CA
    I got mine from OWC and have had no issues at all.
  4. daniel.hershman macrumors newbie

    Aug 26, 2015
  5. brberg macrumors member

    Jun 24, 2010
    I went with Crucial. Got the 16GB upgrade kit (2 x 8GB) to add to my 8GB iMac.
  6. ZipZap macrumors 603

    Dec 14, 2007
    Crucial caused the sleep mode on my 5K to fail. Switched to OWC and had no issues. If you read the comments on Amazon regarding the crucial you will see plenty of issues when mixing Apple and Crucial.
  7. ghoermann macrumors newbie

    Jan 8, 2016
  8. jinyoungkim7 thread starter macrumors regular


    Apr 14, 2010
    Maryland, USA
    Got the OWC 8gb kit to add to the existing 8gb, thanks guys!
  9. iBatmac macrumors member

    Nov 19, 2013
  10. Sowelu macrumors regular


    Aug 15, 2008
    New York City
  11. Suffa macrumors member

    May 11, 2013
    Could I steal this thread for a moment regarding RAM for iMacs. I've been searching the internet but I can't really find anything definitive. I'm trying to figure out if it matters which banks/DIMM you put the RAM in in order for it to run dual channel.

    Some say you should run your identical twin RAM modules in the same BANK others same DIMM pair.

    I upgraded my iMac from 8GB(2x4) to 16GB (2x8) and when I opened the backside the factory sent 2x4GB RAM were placed in slot 2 and 4 and when looking at "about this mac" and "memory", they are top next to each other. And when looking in the sys. info, it says:
    BANK0/DIMM1 empty
    BANK1/DIMM1 empty

    So what I get from this is that the "DIMM0" is paired and not the "BANKS", I don't know...

    I simply don't get it really, does it all matter, dual channel or not, pairing or not? Can't find anything about it from Apple themselves...

    some help please :)
  12. DSTOFEL macrumors 6502a

    Feb 11, 2011
    +1 I bought my 27 inch late 2015 (3.3 GHz i5, 2TB Fusion) with 8GB RAM and installed an additional 16GB of OWC RAM. No problems at all, runs great!
  13. dimme macrumors 65816

    Feb 14, 2007
    SF, CA
    Here is my setup
    Screen Shot 2016-01-29 at 6.07.02 PM.png
  14. squidward macrumors newbie

    Dec 9, 2015
  15. mmomega macrumors demi-god


    Dec 30, 2009
    DFW, TX
    I just received my 32GB of 2133 Kingston HyperX tonight. So I'll be putting it through it's paces of the next week or two to see how the system does.
    In my 2013 I have 32GB of Crucial Ballistix and 1 stick ended up going bad a little over a year. I contacted Crucial and they told me to send it back and I received the replacement stick last week with a little over a week turn around from shipping to receiving.
    IMG_0858.jpg Screen Shot 2016-02-07 at 6.51.26 PM.png
  16. aidanpendragon, Apr 8, 2016
    Last edited: Apr 9, 2016

    aidanpendragon macrumors 6502a

    Jul 26, 2005
    I think you're right, it's the DIMM0/1 slots that must be paired, not the banks. Mine came with the stock 8GB placed like yours. I just upgraded to my 2x8GB Kingston HyperX 2133 and placed them in the same Bank (lower 2 slots...ended up being BANK1). I ran Geekbench and was surprised to see lower scores than with the stock RAM, pulled down by the memory scores (which across the board were 1000 points, or ~33%, lower than initially). I suspect I'm not getting dual channel and will reinsert in the same configuration as factory (i.e. slots 1 and 3 or 2 and 4).

    EDIT: Confirmed, the dual-channel is between DIMM#, not Bank#. Swapped my RAM around and got the expected boost in Geekbench above my factory specs. FYI, from top to bottom as you look at the physical compartment, the RAM slots are:

    BANK0/DIMM1 [top]
    BANK1/DIMM0 [bottom]

    Not what I would have expected, but there it is.
  17. IngerMan, Jun 13, 2016
    Last edited: Jun 21, 2016

    IngerMan macrumors 65816


    Feb 21, 2011
    +1 OWC 16 GB added to make 24GB

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