iMac 5k RAM/Boot Issue

Discussion in 'iMac' started by patmorto, Apr 24, 2018.

  1. patmorto macrumors newbie

    Joined:
    Apr 24, 2018
    #1
    Hi all,

    I have a late 2015 5k iMac. When I first purchased it I replaced the stock 8 gigs of RAM with 32 gigs of crucial memory. It's definitely overkill for what I do, but it was cheap enough so I figured why not.

    Last night my iMac froze up. Force quit wouldn't do anything so I ended up having to do a hard shut down. When I turned it back on all I got was a black screen. I tried booting to safe mode but continued to get a black screen.

    I did a bit of research and determined it could be an issue with the RAM. I took out all of the crucial RAM, replaced it with the original Apple RAM and sure enough it booted right up.

    So, I'm thankful I have my computer back, but now I'm not sure what to do. Would it make sense that one faulty stick would cause the boot problem? I'd like to have as much RAM as possible in my iMac, but I'm not sure if I should experiment to try to find out which stick is faulty. I'm wondering if anyone has had an issue similar to this with aftermarket RAM, and what they did to fix the problem.

    Any advice would be much appreciated!
     
  2. HexAutoParts macrumors newbie

    Joined:
    Apr 24, 2018
  3. DeltaMac macrumors G3

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #4
    Testing for a bad stick doesn't really take a long time, assuming that it is now a dead stick.
    Remove your original RAM, and put a single stick of the Crucial RAM in your iMac. Try to boot. If that works OK, shutdown, and add a second Crucial stick. If you get a failure/black screen, remove that stick, set it aside, and install one of the other sticks, and boot again. Good? add another stick, and try the boot again.
    If you now have three working sticks, shut down, and add that last stick, and try another boot. If it fails, you know it's only one stick - and you know which one has failed.
    You might have more than one bad stick, and the same swap out can help decide which sticks are good, and which are not.
    Or, you might get all the sticks back in, and all is working, without failures. Shutdown, and boot to diagnostics (press and release the power button, and hold the D key. The test will come up. - https://support.apple.com/en-us/HT202731

    You may find that the memory is now all working again. A reseat of the memory sticks is one of the troubleshooting steps when memory issues happen. You might even find that is a good fix, as sometimes that's all it needs.
    Let us know how it goes...
     
  4. spencecb macrumors 6502a

    spencecb

    Joined:
    Nov 20, 2003
    #5
    RAM can be so tricky and cause problems if your computer doesn't like what you put in it. I just got a 27" 5K iMac yesterday, and I realized I have two open RAM slots and want to upgrade my RAM to 16GB. But, I'm wondering if I should replace the existing DIMS in order to not piss off the iMac....
     
  5. DeltaMac macrumors G3

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #6
    More RAM will make your iMac happy! I have never seen a Mac be offended by giving it more RAM (assuming the added RAM is up to specs for your iMac...)
     

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