Mac Pro 2008 RAM 667MHz vs. 800MHz

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messiahmessiah
Posted:
in Current Mac Hardware edited January 2014
16GB of 667MHz, or 8GB of 800MHz?



Which would you go for?

Comments

  • Reply 1 of 6
    kareliakarelia Posts: 525member
    The machine should only recognize one or the other, depending on the model. If it's a Woodcrest or Clovertown model, it uses the 667MHz, and up to 16GB. If it's the new Harpertown model, it can take up to 32GB of 800MHz RAM, but none of the 667.
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  • Reply 2 of 6
    futurepastnowfuturepastnow Posts: 1,772member
    I do not believe you can use the slower 667Mhz FB-DIMMs in the current Mac Pro. I think it requires 800Mhz RAM.
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  • Reply 3 of 6
    messiahmessiah Posts: 1,689member
    No you can definitely use the 667MHz part in the the 800MHz ? there's about a 4% penalty.



    Check out:



    http://www.barefeats.com/harper5.html
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  • Reply 4 of 6
    futurepastnowfuturepastnow Posts: 1,772member
    Quote:
    Originally Posted by Messiah View Post


    No you can definitely use the 667MHz part in the the 800MHz ? there's about a 4% penalty.[/URL]



    Well that's good to know.
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  • Reply 5 of 6
    messiahmessiah Posts: 1,689member
    Yeah I'm just trying to figure out if there are any other implications?



    A 4% performance hit sounds like a good trade-off for half-price RAM (or twice the amount of RAM for that matter).
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  • Reply 6 of 6
    futurepastnowfuturepastnow Posts: 1,772member
    Quote:
    Originally Posted by Messiah View Post


    Yeah I'm just trying to figure out if there are any other implications?



    It's asynchronous (400 on the FSB vs 333 on the memory), but apparently that doesn't cause much of a problem. 4% of a problem, to be exact.



    If you mix different speeds of RAM it should run it all at the lower speed.
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