Confirming 5,1 ram speed

Discussion in 'Mac Pro' started by vasuvasu, Jun 7, 2016.

  1. vasuvasu macrumors member

    Aug 8, 2011
    Purchased a 2010 Mac Pro 5,1 that came with 32gb of aftermarket Crucial memory. It's a 2 x 2.4ghz Quad Core, so even though it shipped with 1333Mhz ram, the previous owner probably put 1066Mhz in there since that's all it needed (and probably what Crucial recommended).

    Is there a way to confirm the ram speed before I swap out the CPUs for dual 6-core units? If it is 1333Mhz, would it show itself in System Profiler as 1333Mhz on a 1066Mhz cpu system or would it say 1333Mhz even though it's only running at 1066Mhz?

    I want to confirm the actual ram speed as opposed to the speed it's running at now on these slower chips.
  2. scott.n macrumors 6502

    Dec 17, 2010
    Just look at the sticker on the DIMMs.

    System profiler will show the speed that the RAM is running at, not its max speed.
  3. G4DPII macrumors regular


    Jun 8, 2015
    In half the time it took you to write that post you could of found out yourself. Are people either becoming this ******* lazy or just plain thick?
  4. vasuvasu thread starter macrumors member

    Aug 8, 2011
    This is the friendliest forum ever.

    Anywho, I didn't see it explicitly listed on the sticker, but now I see 1067 towards the end of the part number. I was looking for PC3-8500 but that's not on there
  5. flowrider macrumors 603


    Nov 23, 2012
  6. ActionableMango macrumors G3


    Sep 21, 2010
    I usually can just do a Google search for the part number silkscreened on the actual chips, which will then bring up the specs including the speed.
  7. h9826790 macrumors G4


    Apr 3, 2014
    Hong Kong
    The 1067 on the part number may be a coincident, not reliable at all, and not all memory module has it's frequency on the part number.

    If you Google PC3-8500, you will get the answer in about 3 seconds, and know that 1066.67x8 = 8533, this is where the 8500 coming from. It's the peak transfer rate (MB's) according to the JEDEC standard.

    For 1333 RAM, 1333.33x8 = 10666, therefore the 1333MHz RAM's standard name is PC3-10600.

    If's a bit confusing, because the PC3-10600 RAM actually NOT running at 1066MHz,. But if you remember 1byte = 8bit, and know that the number should be divided by 8, then you can easily know the speed of the RMA stick buy just looking at the sticker.

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