1333 MHz RAM in a 1066 MHz model?

Discussion in 'Mac Pro' started by dissolve, Aug 17, 2010.

  1. dissolve macrumors 6502a

    Joined:
    Aug 23, 2009
    #1
    Will a 1066 MHz compatible (quad 2010, for example) simply downclock the faster RAM modules? Is this due to the processor or board? I ask because I'm hoping to upgrade my on-the-way 2010 quad to a hex sometime in the future (if possible). Would the 1333 MHz RAM be a better investment if that's the plan? I'll be buying from OWC. Thanks for help.
     
  2. CaoCao macrumors 6502a

    Joined:
    Jul 27, 2010
    #2
    It will downclock and it is because of the CPU
     
  3. Umbongo macrumors 601

    Umbongo

    Joined:
    Sep 14, 2006
    Location:
    England
    #3
    As CaoCao said it will down clock. The 2010 Mac Pros all come with 1333MHz memory according to the manual.
     
  4. Transporteur macrumors 68030

    Joined:
    Nov 30, 2008
    Location:
    UK
    #4
    If I were you, I'd definitely buy 1333MHz modules.

    The 3.33GHz hex core also uses this memory so there is no reason to settle for 1066MHz ones.
     
  5. bzollinger macrumors 6502a

    bzollinger

    Joined:
    Aug 1, 2005
    #5
    The 1333MHz RAM will work in all 2010 MPs, but not all of them can run it.

    The 2.8, 3.2 Quads, and the octos run at 1066. But the 3.33GHz hex, and the dodacores can run at full 1333MHz speeds.:)

    If the price is the same or very close I'd buy the faster ram.
     
  6. dissolve thread starter macrumors 6502a

    Joined:
    Aug 23, 2009
    #6
    I'd never heard this. So you think all 2010s will ship with the same RAM modules? I guess that could save cost as Apple buys in bulk. Either way, it's only a few more bucks from OWC for the faster RAM so it seems an easy choice. Thanks all :)
     
  7. Umbongo macrumors 601

    Umbongo

    Joined:
    Sep 14, 2006
    Location:
    England
    #7
    Here is the page from the manual

    [​IMG]
     
  8. dissolve thread starter macrumors 6502a

    Joined:
    Aug 23, 2009
    #8
    Awesome, thanks. Didn't know they had posted the manual already...going through it now :)
     
  9. flatfoot macrumors 65816

    Joined:
    Aug 11, 2009
    #9
    It's dodeca, actually dodeka, since it's greek.

    BTW:
    To whom it may concern: An 8-core machine is an octo, not an octad, like many on these forums like to call their machines.
     
  10. VirtualRain macrumors 603

    VirtualRain

    Joined:
    Aug 1, 2008
    Location:
    Vancouver, BC
    #10
    I wonder what timings the RAM have.

    It's often the case that the SPD timing table will tighten timings (reducing latency) when RAM modules are operated below their rated speeds. For example, 1333 modules rated for CAS 7 might run at CAS 6 at 1066 speeds. (assuming Apples firmware uses the SPD to configure the memory controller vs hard coding a conservative set of timings)

    While the benefits are minimal, it would be interesting to pull the SPD table data with a utility in Windows if anyone gets the chance.
     

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