riMac Upgrading RAM

Discussion in 'iMac' started by MowingDevil, Nov 1, 2014.

  1. MowingDevil macrumors 68000


    Jul 30, 2008
    Vancouver, BC & Sydney, NSW
    Anything people should when upgrading the RAM in the new iMacs? Anyone have issues? Are certain brands better? Is there only one type that will work or could you buy a lesser quality or less optimized? I was going to order a kit made by Crucial.
  2. newbish macrumors member

    Oct 25, 2014
    i've bought and received 2 16GB-kits made by Crucial yesterday. Installed them and it works just fine. 32GB on the riMac :cool:
  3. Bryan Bowler macrumors 68040

    Sep 27, 2008
    Crucial is the way to go. You can save a significant amount of money by ordering the Crucial RAM from B&H Photo (added bonus, no sales tax unless you're in NY) or through Amazon.

    It is very easy to install.

  4. robgendreau macrumors 68040

    Jul 13, 2008
    There are actually installation instructions under the hood; you just push the button behind the cord inlet and the little cover should pop open.

    If you can put a DVD in a computer you can swap the RAM.

  5. MowingDevil thread starter macrumors 68000


    Jul 30, 2008
    Vancouver, BC & Sydney, NSW
    Perhaps I should have been clearer, its not the process (I've done it before) of upgrading the RAM I'm concerned about, its what to buy. If I'm ordering this stuff online to save a couple hundred, I just want to make sure I get the right kind. Is there only one type that works? Is there different speeds or qualities? Crucial sounds like the best. What specs do we need for the retina?

    DDR3, 1600MHz, PC3-12800, CL11, SODIMM, 204pin

    Will that do the trick? Just wondered if there's anything we need to know beyond that.
  6. iczster macrumors member

    Oct 23, 2014
    Ive ordered the stock 8GB and 16GB from crucial. Do they need pairing in banks or any DIMM can go anywhere?

    eg. slot 1 and 3 / slot 2 and 4
  7. duky, Nov 1, 2014
    Last edited: Nov 1, 2014

    duky macrumors 6502

    Jun 25, 2007
    North Carolina
  8. ikm19 macrumors 6502


    Nov 1, 2007
    Doesn't matter if they are of 1600Mhz
  9. Onimusha370 macrumors 6502a

    Aug 25, 2010
    ordered 2 8gb sticks from crucial the other day.
    After installing my iMac refused to boot... took the back off again and found i hadn't clipped one of the sticks in properly!
    Working brilliantly with 24gb of ram, hoping this machine will last me a good 6 or 7 years now :)
  10. apfelmann macrumors 6502

    Jul 23, 2007
    voltage 1.35V is recommended
    it should say DDR3L
    L stands for low voltage
  11. haddy macrumors regular

    Nov 5, 2012
    Yeah that's what they call them...."kits".
    But does anyone know if you can get 16GB RAM modules to go in an iMac............giving 64GB of RAM?
  12. 5iMacs macrumors regular

    Oct 25, 2014
    I bought the base RAM and went 3rd-party with some premium Crucial RAM sticks (16GB), and it's been great, even though they are $30 more:

    Crucial Ballistix Sport SODIMM 16GB Kit (BLS2K8G3N18AES4)

    These are recognized by the 5k iMac and automatically run at 1866 MHz. It's significantly faster than the stock RAM, about 25% on the Geekbench and other memory benchmarks.

    (Note that you lose 1/2 of the speed-up when you include the stock Apple RAM in the mix, so I've set those aside for now. It's interesting that you still get 1/2 the speed benefit though.)

    But what does faster RAM actually get you?

    Well, I switched between the old and new RAM about 10 times testing various things. Other than memory benchmarks, the main improvement I've seen is with the 'WindowServer' process. This is the thing that is constantly taking all of the bitmap renderings from your browser, Finder, Preview, etc windows and feeding them to the GPU. This activity has nothing to do with GPU or CPU speed, it's just copying data so it's memory-speed bound.

    And it gets a noticeable boost. Running with about 5 apps, 30 windows (mostly Safari) when I move a Safari window in circles over all of the other windows it's definitely repainting at a higher and more consistent framerate. Also the CPU load for WindowServer (in Activity Monitor) drops from 15% from 12%. It just has an easier time with faster memory.

    I don't want to overstate it, it's not night and day, but I would rather stick to 16GB than add in the slower additional 8GB for now.
  13. newbish macrumors member

    Oct 25, 2014
    i'm not sure about that. although i think it is a technical wall that doesn't allow such high addressable space for the iMac.

    are there 16GB ram sticks of this size (204 pins laptop memory) though?

    is it possible for you to set up a 8GB RAM disk and do a blackmagic disk speed test? let it run for abit and see how fast it actually goes. I did tests on mine and it went up to 4.5~4.7GB/s Read/Write
  14. 5iMacs macrumors regular

    Oct 25, 2014
    Correct on the RAM limits, 32GB is the max for the iMac's CPU. One of the big advantages of the Mac Pro.

    I've haven't set up a RAM disk on a Mac since System 7, but if it's not too much trouble I'll give it a try.
  15. newbish macrumors member

    Oct 25, 2014
    awesome! you just have to enter this command exactly as it is in the Terminal app.

    you can easily unmount it when you are done by ejecting it like a mounted thumb-drive.
  16. MowingDevil thread starter macrumors 68000


    Jul 30, 2008
    Vancouver, BC & Sydney, NSW
    Thats interesting, because one dealer I found had them $11 cheaper than the regular Crucial kits. So no risks in going w/ these sticks over the 1600 ones?
  17. 5iMacs macrumors regular

    Oct 25, 2014
    Thanks for the RAM disk tip.

    That speed test is a little freaky the way it keeps getting faster and faster with each run, but if it helps, it leveled off at 4.6 GB/s
  18. newbish macrumors member

    Oct 25, 2014
    mine took quite a while to climb up to 4GB/s++ as well.
    seems like it may be a minor difference in speed. my read was ~4.3GB/s while write went up to ~4.6-4.7GB/s at its peak.

    i'm not sure if there are other tests we can run to see the difference
  19. adww12321 macrumors member

    Dec 24, 2012
    One tip i'd add to anyone who is opening up that little door in the back to seat he RAM--

    Use a suction cup to lift the panel off, as opposed to trying to lift the thing out with your fingernails. It is easier :)
  20. 5iMacs macrumors regular

    Oct 25, 2014
    They are running great for me, and I've put them through a lot of load, so I'd say that's a great deal. I spent $160.


    Yup. As I mentioned, there are not a lot of things that will show an improvement, just moving memory quickly. As soon as you dilute it with some CPU overhead, any speed improvement becomes negligible.
  21. MowingDevil thread starter macrumors 68000


    Jul 30, 2008
    Vancouver, BC & Sydney, NSW
  22. iczster macrumors member

    Oct 23, 2014
    Cool. So I can keep the 2 x 4GB and add the 2 x 8 GB and its not slot specific?
  23. TerrorOFdeath macrumors member


    May 15, 2008
    Im planning on buying these.


    DDR3L-2133MHZ (PC3-17000)
    DDR3-2133MHZ CL11-12-13 @1.35V or 1.5V

    Anyone knows if they will work?

  24. firsmith macrumors member

    Oct 16, 2014
    It sounds like there's two versions of the crucial? 1600 and 1666 - or "premium"? Is this correct, or have I read things wrong?

    Any suggestions on best place to order these for shipping in Canada (all in cost)? Can I buy at Best Buy? I'm in Vancouver


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