Memory performance

Discussion in 'Mac Pro' started by rdsii64, Jul 6, 2013.

  1. rdsii64 macrumors regular

    May 14, 2008
    First let me apologize for shotgunning questions about my new machine all over the forum. Now on to the next one. One of the upgrades on the list of must haves is a memory upgrade. My mac Pro is a 3.1 but the seller shipped it with 8 gigs of 667 ( four 2 gig sticks) So far my plan to save for four 4 gig sticks so if I ever actually need more, I have room for another upgrade.

    First, will I even notice the 133 Mhz difference between 667 and 800 mhz memory?

    Second, I have read that if all the memory slots are filled, the memory performs better. If I understand this correctly if your are going to install a 16 gig kit, filling all the slots with 2 gig sticks is better than filling half of them with 4 gig sticks. Do I understand this correctly? If so, how much REAL DIFFERENCE is there?

    Third, for final cut pro x, motion 5, and compressor 4 to function well, how much memory do I actually need?
  2. Tesselator, Jul 6, 2013
    Last edited: Jul 6, 2013

    Tesselator macrumors 601


    Jan 9, 2008
    First, no you won't notice the difference. Maybe if you're clocking a ramdrive with an I/O benchmarker or something. Geekbench scores a tad higher with 800 but that's a pretty meaningless benchmark anyway.

    Second, Two Pair over and under I think is as fast as it gets. MP3,1 has only dual-channel IIRC. Although if you upgrade from only two DIMMs to both two-pair and also 800MHz then I do think you might notice some difference.

    Third, The answer to this question is always: As much as you can afford. :) I recently tried with 5 or 6 different ammounts and I noticed the difference between 16GB and 24GB but not between 24GB and 32GB. At 24GB OS X settles down to a nice quite state and apps such as you name perform very well. If you add four 4GB DIMMs you'll have the 24GB mentioned. 4x4GB 667 DIMMs should be about $150 to $175. And you do NOT need the BS "Apple Approved" RAM with the jumbo heatsinks. Buy used server memory off ebay.
  3. rdsii64 thread starter macrumors regular

    May 14, 2008
    Thanks for the answer. So unless I want YouTube benchmark bragger points (not hate'n on YouTube ) the 667 stuff I have is good enough to get work done. I just need more than the amount I have. A ram kit and an OpenCL graphics card and I can get started. The other stuff will come later

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