Is it necessary for both memory slots to be equal in size?

Discussion in 'MacBook Pro' started by zipster, Mar 20, 2012.

  1. zipster macrumors 6502

    Jan 6, 2011
    Hi all,

    I'd like to upgrade the RAM on my mid-2009 MacBook Pro. Do both memory modules have to be the exact same size (ie: 2 2GB modules in each slot) or can they differ (ie: 1 2GB module and 1 4GB module). I understand that Apple recommends having the same size for both slots, but was wondering if it hampered performance (or something worse).

    Thanks for your help!
  2. miles01110 macrumors Core


    Jul 24, 2006
    The Ivory Tower (I'm not coming down)
  3. Bear macrumors G3

    Jul 23, 2002
    Sol III - Terra
    It does affect performance a tad. At the price of memory, you might as well go from 2x2GB to 2x4GB.

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