RAM for Mac Pro 5.1

Discussion in 'Mac Pro' started by KLWN, Apr 8, 2015.

  1. KLWN macrumors member


    Apr 1, 2015
    Hi guys,

    im currently looking for new RAM for my Mac Pro 5.1 (Six Core). I found this RAM modules but im not sure if they work with my Mac.

    What do you guys think?

    best regards,
  2. bsbeamer macrumors 65816

    Sep 19, 2012
  3. dmylrea macrumors 68020


    Sep 27, 2005
    Why pairs? Wouldn't you want a set of 3 for best performance (or 4 for slightly less performance but more memory capacity)?
  4. flowrider macrumors 601


    Nov 23, 2012
    The last Mac Pro to require that RAM be installed in pairs was the 3,1 2008 model. The 4,1 and 5,1 cMP work best with RAM installed in threes because the CPUs have three memory channels.

    BTW, my memory supplier since 1986 has been:


    Quality at a reasonable price.

  5. bsbeamer macrumors 65816

    Sep 19, 2012
    Had memory related issues with 5,1's and 3x8GB sticks in the past on client's workstations. The machines performed more reliably with 2x8GB sticks or 4x8GB sticks. Ended up taking one stick out one machine, added it to the other and there were less memory-related crash issues when rendering video. None were showing as bad sticks, but sometimes they do not...

    This absolutely could have been an isolated incident, but when upgrading or configuring, it's just a recommendation. 3x16GB on a 3.33 works great.
  6. flowrider macrumors 601


    Nov 23, 2012
    ^^^^Hard to believe that a 5,1 would work better with four sticks than three? The fourth slot is electrically tied to the third slot. If the third memory slot is left MT, a stick in the 4th slot will not be recognized.

    From personal experience, I have a dual CPU 5,1 with 6 of the eight slots populated and no RAM issues with quality DMS RAM.

  7. lewnworxx macrumors member

    Mar 19, 2015
    I'm with Lou on that one. Prior to the CPU upgrade I had all 8 slots loaded. Post CPU upgrade I picked up 3 8GB's from DMS to do the triple channel thing. In benchmarking my renders between the two flavors of ram, I see a 13% decrease in render times, and nearly a 18% decrease in bake times by going to triple channel RAM. The cost delta is marginal.
  8. RoastingPig macrumors 68000


    Jul 23, 2012
    i once seen on here a guy using the nmp ram in his cmp, anyone have that picture?
  9. flowrider macrumors 601


    Nov 23, 2012
    ^^^^You can, it will fit and work just fine. But you will not see the RAM speed of the nMP (1866MHz).


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