iMac 5K @ 1333mhz after ram upgrade

Discussion in 'iMac' started by slvrscoobie, Jul 23, 2015.

  1. slvrscoobie macrumors 6502a

    slvrscoobie

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    NJ
    #1
    So I bought a 5K iMac last week and just got the ram today. Got GSkill 1600mhz 8GB sticks. Needed more than 8gb but didnt need a full 32, so I added the 8gb sticks to the 2 4gb sticks for a total of 24gb.
    Booted fine and sees all 24gb, but its only registering at 1333mhz instead of the 1600mhz I would expect.
    Did I miss the boat and the latency difference cause the ram to clock down so they can match? Or am I missing something else?
     
  2. rkaufmann87 macrumors 68000

    rkaufmann87

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    #2
    Return the GSkill and buy either Crucial or OWC RAM.
     
  3. Chundles macrumors G4

    Chundles

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    Jul 4, 2005
    #3
    The RAM you put in isn't 1600MHz. It's 1333MHz.
     
  4. slvrscoobie thread starter macrumors 6502a

    slvrscoobie

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    #4
    Nope. It's 1600mhz. It's just that as I thought the latency of the 8gb is too different from the 4gb so it's clocked slower to match them. Confirmed by another reader.
     
  5. slvrscoobie thread starter macrumors 6502a

    slvrscoobie

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    #5
    Yup that's what I did :rolleyes:
    Come on, don't be stupid. ImageUploadedByTapatalk1437741336.646987.jpg
     
  6. Chundles macrumors G4

    Chundles

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  7. slvrscoobie thread starter macrumors 6502a

    slvrscoobie

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    #7
    What you think gskill really sent me the wrong ram in the right package, even though other members have confirmed that different sticks of 1600mhz ram with different cls will boot at 1333 instead.
     
  8. Chundles macrumors G4

    Chundles

    Joined:
    Jul 4, 2005
    #8
    Yep. That's what I think. Or crap RAM.

    Never installed 1600MHz RAM into an iMac and had it clock down. It's either wrong or crap. Either way you need new RAM.
     
  9. slvrscoobie thread starter macrumors 6502a

    slvrscoobie

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  10. Chundles macrumors G4

    Chundles

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  11. slvrscoobie thread starter macrumors 6502a

    slvrscoobie

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    #11
    No problem here now that I know it's just the 4gb/8gb combo being a pain.
     
  12. Alesc macrumors 6502

    Alesc

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    Nov 11, 2014
    Location:
    France
    #12
    You're right ;) Your new RAM is CL9, so the Mac is running all the modules at CL9... The RAM sold with Macs is CL11 @ 1600MHz, so the computer must run them @ 1333MHz to match the CL9... :)
     
  13. Alesc macrumors 6502

    Alesc

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    Nov 11, 2014
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    France
    #13
    I've added 2x8GB modules to the 2x4GB modules sold with my iMac: no problem with my 24GB. But I've bought 1600MHz CL11 modules ;)
     
  14. slvrscoobie thread starter macrumors 6502a

    slvrscoobie

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    #14
    Yup, Shoulda noted the CL11 - Took out the 2x4gb and its 1600mhz again. I think Ill leave it for now, see how 16gb holds up, buy another 2x8gb CL9 if I find memory compression or anything going on with LR, PS, Chrome, ect all open.
     
  15. phpmaven, Jul 28, 2015
    Last edited: Jul 28, 2015

    phpmaven macrumors 68040

    phpmaven

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    Location:
    San Clemente, CA USA
    #15
    I have 1866mhz ram and it runs at 1867mhz. If your RAM is getting clocked slower than it's rated for, then there's something wrong.

    Going back and reading the original post, it looks like you are mixing new sticks with old. You do know that all of the sticks will run at the speed of the slowest ones, right?
     
  16. aliensporebomb macrumors 68000

    aliensporebomb

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    Jun 19, 2005
    Location:
    Minneapolis, MN, USA, Urth
    #16
    Haven't had this issue - ended up getting 16 GB of OWC 1600 mhz ram and I'm at 24 gigs with 1600 mhz speed.

    I'll get another 16 GB at some point for the full 32.
     

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