"Matched Pair"

in Current Mac Hardware edited January 2014
my friend and i, both long-time mac users, are having an argument as to what exactly apple and memory companies mean when they say refer to a "matched pair" of memory sticks. this came about when i was upgrading my imac's ram to 2gb (1gb x 2). my friend told me to make sure that the sticks i bought were labeled as a "matched pair".

i think, but am not 100% sure, that a matched pair is merely two sticks of memory with the same specs from the same company. however, my friend believes that the "matched" quality is a specification of memory that only some sticks have, and that you need to buy them in matched sets, instead of just buying, as i would have done, 2 identical sticks from a company. i've done some research on this, but i cannot find any site or forum post that explicitly states which view is right. can someone who knows set this straight? thanks!


  • Reply 1 of 2
    With the current Santa Rosa chipsets, dual channel memory configuration has become quite flexible. You can even use RAM of different size and with different timing (in case of different timing, all memory is accessed at the speed of the slowest module).

    When you install two RAM modules of different size (e.g. slot A: 1GB and slot B: 2 GB), only the addresses common to both modules are used in dual mode (in my example 1GB on slot A and B), and the "extra" memory on the larger module is operated in single channel mode (1GB in slot B). In my example, you could use 2 GB memory with dual channel (1 GB + 50% of the 2GB), and 1 GB (the other 50%) will run in single channel mode.

    So the optimal configuration is two install two RAM cards of same size and timing, but as I explained, also mixed setups will use dual channel access as much as possible. There is no need to buy matched pairs of RAM, unless you find a way a way to overclock your system.
  • Reply 2 of 2
    g-newsg-news Posts: 1,107member
    Matched pairs are, as was already said, 2 modules of the same spec and size.

    They don't need to be of the same brand, theoretically, if the specs are identical.

    Bundles that are labelled "matched pair" are just that, a matched pair of 2 sticks with same specs and size. Nothing more and nothing less. Your friend is wrong and you're right.
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