1.35v Ram and 1.5v Ram Mac pro mid 2012

Discussion in 'Mac Pro' started by VillasManzanill, Mar 6, 2015.

  1. VillasManzanill macrumors regular

    Mar 7, 2012
    I have a mid 2012 mac pro with one xeon x5690 and also 2x4gb ram 1333mhz.
    i want to buy one 16gb ram stick 1333mhz.
    Just wondering if i can use one of the new sticks that only needs 1.35v DDR3L and if is going to be compatible with the other sticks that are 1.5v
  2. mikeboss macrumors 65816


    Aug 13, 2009
    AFAIK these low-voltage (1.35V) DIMMs have to be compatible with 1.5V, too. but you can't mix registered and non-registered modules. I assume that your 4GB DIMMs are non-registered whereas the 16GB module is registered.
  3. VillasManzanill thread starter macrumors regular

    Mar 7, 2012
    Do they sell UNREGISTERED 16gb RAM so i can then mix them with my current setup?
  4. Umbongo, Mar 6, 2015
    Last edited: Mar 6, 2015

    Umbongo macrumors 601


    Sep 14, 2006
    Not that you can mix in and they are much more expensive. It is cheaper to buy two 16GB Registered DIMMs .
  5. Prince134 macrumors 6502

    Aug 17, 2010
    My experience with mixing different voltage was bad. They lower speed to 1066mhz. 1.5v was my best result. It pay me two eBay returns before I strictly put all sticks to be 1.5v and I have 128gb running at 1333mhz.
  6. VillasManzanill thread starter macrumors regular

    Mar 7, 2012
    What if i buy 2 of those Rams from Amazon $108 each 16gb. and is just use those 2 in my system, do they work properly at 1333mhz without mixing them with the other ones that are Unregistered?
  7. Surrat macrumors 6502


    Jun 20, 2014
    United States
    Yes, you can do that.
  8. carylee2002 macrumors member


    Jul 27, 2008
    Best thing to do is to look at macsales.com and look at their ram configurations for your Mac Pro. The ram has to be ECC and should have the apple sensor on it. I just purchased new ram for my 5,1 mid-2010 to max at 48gb from macmemory.net at a sale price but it has the apple chip on them also.
  9. VillasManzanill thread starter macrumors regular

    Mar 7, 2012
    was it as cheap as 108 USD for 16gb of ram?
    apple sensor? i think you got a sales pitch from them, i don't really think thats the case. ram its ram.
  10. DougTheImpaler macrumors 6502a

    Feb 28, 2006
    Central Illinois
    The memory controller should run everything at the most "compatible" settings, but I would not mix ECC with non-ECC memory. The memory in my 4,1 is 2x8GB Crucial Ballistix Sport 1.35 DDR3-1600, and then when I bought the third memory channel I thought I was buying another 1x8 DIMM identical to the others. What I bought was 8GB of Crucial Ballistix (not sport) 1.5v DDR3-1600. Since my W3570 only supports DDR3-1333, CPU-Z in Windows 7 reports that it's all running at 1.5v, DDR3-1333 speeds. The 2x8GB kit is capable of running at 1.5v, since that's JEDEC spec for DDR3-1333.

    Along with not mixing and matching ECC and non-ECC, I would not buy 1.65v memory - that's higher than JEDEC spec and I don't believe the Xeon's memory controller supports higher-than-spec RAM.

    All things considered, mine probably works OK because it's all the same manufacturer and compatible timings. I consider myself lucky to not have to send that third 8GB back to get the right stuff. The only way to be 100% sure is to get all matched memory.
  11. 666sheep macrumors 68040


    Dec 7, 2009
    What you can't mix:
    – registered and unbuffered

    What you shouldn't mix:
    – ECC and non-ECC (it will usually work but can produce strange side effects)
    – dual ranked and quad ranked sticks (it will usually lower the memory clock, depending on setup

    What you can mix without issues:
    – different RAM speeds, upwards ofc
    – different voltages up to factory one (i.e. 1.5 with 1.35V, all PC3L memory can run @1.5V)

    "Apple approved sensors" are unicorns in my experience. I didn't meet a single stick which wouldn't show temperature read and/or cause fans rpm increase. I used tons of Samsung, Hynix, Elpida, Kingston, Micron, Integral, Nanya sticks of different capacity, voltage and ranks.
  12. VillasManzanill thread starter macrumors regular

    Mar 7, 2012
    well i just click buy and they were $99 USD each! i bought 2. hope they work.
  13. Keter macrumors member

    Jan 30, 2015
    I am about to list a Crucial 32GB 13333MHz ECC kit (4x 8GB) for Mac 5,1 on eBay for $320.

    PM me if you are interested.
  14. carylee2002 macrumors member


    Jul 27, 2008
    Let us know how they turn out. I myself cannot risk being shutdown due to ram problems when editing 4k footage. I can't have paying customers wait due to equipment failure on my part.

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13 March 6, 2015