Mix/Match RAM???

Discussion in 'Mac Pro' started by bbadalucco, Aug 14, 2009.

  1. bbadalucco macrumors 6502

    Joined:
    Jan 4, 2009
    #1
    I bought a refurbished 3.2 Octo MacPro (2008) which came with the 2x1 sticks of RAM. I have since removed that ram and added 4, 4gb Ram sticks for a total of 16. I was curious if I could add the two single gb sticks since I still have a total of 4 open slots?

    If so, would it work alright with the crucial ram I have since installed?
     
  2. Tallest Skil macrumors P6

    Tallest Skil

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    Aug 13, 2006
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    1 Geostationary Tower Plaza
  3. bbadalucco thread starter macrumors 6502

    Joined:
    Jan 4, 2009
    #3
    Cool, wasn't worried about the different brands as I was the size. Appreciate the feedback.
     
  4. pprior macrumors 65816

    Joined:
    Aug 1, 2007
    #4
    Agree with above. As an additional note, the first 2 pairs on each riser I believe are accessed faster than the second 2 pairs, so if you're mixing ram density put the higher amount of ram in slots 1 and 2 on each riser then the lesser stuff in 3 and 4 as needed.
     
  5. bbadalucco thread starter macrumors 6502

    Joined:
    Jan 4, 2009
    #5
    My system doesn't recognize the two extra gigs? There should be a total of 18 now, but the system still only shows 16. Slots 1&2 of each tray have the two 4gb Crucial sticks and slot 3 of both trays have the 1gb that came with the system.

    Any ideas?
     
  6. flatfoot macrumors 65816

    Joined:
    Aug 11, 2009
    #6
    The DIMMs have to be added as matched pairs; this also means you have to put the two 1GB-ones into slot 3&4 of one tray – that's all. ;)
     
  7. bbadalucco thread starter macrumors 6502

    Joined:
    Jan 4, 2009
    #7
    Sounds good..thanks
     

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