Mac Mini '12 - New 1600 mem runs @1333, what gives?

Discussion in 'Mac mini' started by Omega Mac, Jan 7, 2015.

  1. Omega Mac macrumors 6502

    Aug 16, 2013
    Any ideas folks. Upgraded the ram with 2 x 8GB stick of 1600Mhz PC3L and system is reporting it's MHz speed as 1333.

    Any ideas / tips?
  2. Omega Mac thread starter macrumors 6502

    Aug 16, 2013
    Further update. (to note) These sticks are packaged and sold as paired.

    Both 8GB sticks in inserted in to either mem slot when used solo run @1600Mhz but when they are both insereted (regardless of slot) to make up the full 16GB they clock down to 1333Mhz.
  3. Celerondon macrumors 6502a


    Oct 17, 2013
    Southern Cal
    Quick With One & Slow With Two?

    What are the brand and part number for those memory sticks? For years my machines have autoconfigured with no problems.

    That sounds weird to me.
  4. dyt1983 macrumors 65816

    May 6, 2014
    Do you know the latency of the RAM installed? Sometimes the latency is better at a slower speed. Just a guess based on some of the threads on ram posted in the iMac forum.
  5. Omega Mac thread starter macrumors 6502

    Aug 16, 2013
    Manu: G.Skill
    Name: Ripjaws

    DDR3L-1600 CL-11-11-11-28 1.35v
    PC3L-12800 8GBx2 SO-DIMM

    I have a trade supplier for memory and thus far for all my various machines I've source memory from them and had no problem upgrading any machine.

    Since I have 2 x 2012 Mac Mini's 2.3Ghz, I tested the memory in both machines and it's behaves the same once you put both modules in together they clock down to 1333Mhz but independently installed and they clock up to 1600Mhz

    - Interesting point about latency.

    Perhpas they are simply incompatible. I had an issue many years ago from another supplier who forgot I was ordering it fora mac and didn't check it. Once returned they got me the right type.
  6. Gjwilly macrumors 68030

    May 1, 2011
    SF Bay Area
    I'm guessing they're not truly 1.35v.
    They're 1.5v and the two of them together pulls the power down below spec and the Mac throttles the speed to compensate.
    Of course I know nothing about memory.
  7. WilliamG macrumors G3

    Mar 29, 2008
    2012 Mac mini doesn't need 1.35V RAM. How do I know? Cause I'm running 1.5V RAM in my 2012 mini no issues. For Haswell-based systems, depending on the system it might not boot with 1.5V RAM (my Intel NUC Haswell-based system won't even post without 1.35V RAM, but my Haswell 2014 5K iMac is using 1.5V RAM without issues).

    Anyway, that memory may just be slightly incompatible. I'd send it back and get some Crucial or Corsair - try something different.
  8. Omega Mac, Jan 8, 2015
    Last edited: Jan 8, 2015

    Omega Mac thread starter macrumors 6502

    Aug 16, 2013
    I can't tell if it's drawing 1.5V instead of 1.35V.

    I've tried it in both Mini 2012 servers and have replicated the results to satisfaction the behaviour is identical. I've also done a reset of the NVRAM and SMC resets just in case.
  9. WilliamG macrumors G3

    Mar 29, 2008
    Exchange them. No need to waste anymore time.
  10. paulrbeers macrumors 68040

    Dec 17, 2009
    Generally speaking, the slower the mhz that your RAM is running, the lower the latency. Thus, 1333mhz with lower latency (i.e. 9) vs 1600mhz with higher (11) will actually have (roughly) the same throughput and cause no loss in system performance.

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