So can you use 4GB in a 2.16Ghz Core2 Duo or not?

Discussion in 'MacBook Pro' started by CMD is me, Dec 6, 2007.

  1. CMD is me macrumors 6502

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    Dec 7, 2006
    #1
    Sorry to post another 3 vs 4GB RAM questions but this has me stumped (this is specific to the Core2 Duo)...

    I read (here) that the Core2 Duo chips can see up to 3.3GB with 2x2GB modules. I have a 2.16 (late 06). However trying to buy a matched pair online I'm being told 2x2GB modules may not work right in the 2.16, only the 2.2+. Huh? Won't what works in the 2.2 also work in the 2.16 only the 2.16 will show 3.3GB? The price difference is only $25. So why not get a matched pair and extra RAM? Is this a case of the sales guy won't go off the spec sheet?

    According to OWC that can increase the performance 50% during heavy loads (see the HOG test results)!

    Additionally the guy said my system USE to be on their sheet as able to use 2x2GB however they have since changed that. Huh? The guys at OWC usually know their stuff.
     
  2. olliebraves20 macrumors regular

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    Nov 27, 2007
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    Lansing, MI
    #2
    Core 2 Duo machines that are not Santa Rosa can recognize a potential 3.3 GB ....the top 700 MB is wasted, so the practical maximum is 3 Gb . This is a hardware limitation.

    With 4 GB installed, these machines will report 4 GB in System Profiler, but the operating system will only use 3.3 GB.

    To sum all that up yes you can install 4GB of RAM but there isn't a huge benefit of just having the 3GB installed. The part about "not working right" is that you lose the top 700MB.....

    Hopefully that help you...
     
  3. CMD is me thread starter macrumors 6502

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    Dec 7, 2006
    #3
    Thanks. That's what I thought. OWC's test on matched pairs (see above link) shows a pretty big performance gain in Photoshop when 50% of the RAM is used elsewhere -- 169s compared to 98s! If that is true in real world usage (I typically do have 10 apps open at once), then it is a much larger benefit than the 3-5% increase I've read previously.
     
  4. aviddk macrumors regular

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    Oct 18, 2007
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    SW Oregon
    #4
    I have 4GB of Crucial memory installed in my C2D 2.16 White iMac running 10.5.1. About this Mac reports 4GB but Activity Monitor has never show over 3GB. I expected it to show 3.3 GB like OWC said it will. Comments?
     
  5. macrumorino macrumors regular

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    Dec 25, 2007
    #5
    I don't see 3.3. gb

    I got 4gb for the 2.16ghz Imac and, sure enough, it only sees 3gb. Not 3.3 gb, either...
     
  6. CMD is me thread starter macrumors 6502

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    #6
    Yep that's right. You'll only see 3.3 which is the max.
     
  7. Consultant macrumors G5

    Consultant

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    #7
  8. macrumorino macrumors regular

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    Dec 25, 2007
    #8
    Argh... PLEASE STOP REPEATING THIS CANARD.

    The system only sees 3 GB. IT DOES NOT SEE 3.3 GB. IT ONLY SEES 3 GB.
     
  9. heatmiser macrumors 68020

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    Dec 6, 2007
    #9
    So effectively the top gig is wasted; it's 3gb, and not 3.3gb.
     
  10. ayeying macrumors 601

    ayeying

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    #10
    Mine only uses 3GB, but the performance boost from 3GB to 4GB is amazing for the macbook.
     
  11. acearchie macrumors 68040

    acearchie

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    Jan 15, 2006
    #11
    But is it not more beneficial to have the dual channel memory?

    Therefore a 2x2GB will show a performance increase over a 1x1GB + 1x2GB?

    This situation doesnt apply to me Im just trying to help other people in this situation!
     
  12. heatmiser macrumors 68020

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    #12
    Eh? How is there a 4gb boost if you're using 3gb?
     
  13. ayeying macrumors 601

    ayeying

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    #13
    Dual channel. I lost dual channel when i used 1x2GB + 1x1GB. It lagged a lot of stuff, especially the eye candy in Leopard. After I switched to 2x2GB, that lag went away, my FPS in certain games went up, I can switch between windows without any problem or delay, even got my start up (pressing button to log on screen) in about 6-8 seconds.
     
  14. heatmiser macrumors 68020

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    #14
    I had no idea it made that much of a difference. Thanks! I guess I'll keep waiting for the 2x2gb prices to drop instead of buying a 1x2gb stick now.
     
  15. ayeying macrumors 601

    ayeying

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    #15
    I didn't believe it made that much of a difference either. I was quite amazed with the boost. I only upgraded to 4GB in the first place because I saw a good sale for 2x2GB, so I just took out the old 2GB in the macbook and gave it to my dad's iMac, upping his system from 2GB to 3GB.
     
  16. CMD is me thread starter macrumors 6502

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    Dec 7, 2006
    #16
    Ditto... running 2 x 2GB is noticeably quicker than 1 x 2 and, of course, 1 x 1. I've run every configuration possible and for the minor cost, 2 x 2 is worth it if running multiple apps.
     
  17. HFU macrumors regular

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    Jun 8, 2005
    #17
    MBP C2D Napa and 4GB RAM Recognized!

    Running Tiger 10.4.11 with 4GB RAM:

    About This Mac: 4GB
    System Profiler: 4GB
    Activity Monitor: 3GB

    Running Leopard 10.5.0 with 4GB RAM:

    About This Mac: 4GB
    System Profiler: 4GB
    Activity Monitor: 4GB

    Leopard 10.5.0 also updated pre-N Wireless Network Adapter to (802.11 a/b/g/n) which can be verified under Network Utility.

    Apple must have done some improvement in Leopard to take advantage of full 4GB memory addressing. So much about 945PM (Napa Chipset) hardware limitation from Intel and Apple marketing team!
     
  18. Consultant macrumors G5

    Consultant

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    Jun 27, 2007
    #18
    You need to read the thread referenced in #7. Been there, done that.
     
  19. HFU macrumors regular

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    Jun 8, 2005
    #19
    You are right! 3.3GB is the max usable memory space for pre-SR MBP. Thanks for the clarification.
     
  20. macrumorino macrumors regular

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    Dec 25, 2007
    #20
    Why, why, why do you say 3.3 GB??

    It is only 3 GB.

    This is like the third time at least in this very thread that this has been repeated. :eek:
     
  21. LeftoverCrack macrumors member

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    Jan 2, 2008
    #21
    my system uses 3.3. yours must not. RELAX it's okay. things are different sometimes. you have repeated yourself three times too. it's not a huge deal man.
     
  22. macrumorino macrumors regular

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    Dec 25, 2007
    #22
    Can you prove that, please?
     
  23. LeftoverCrack macrumors member

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    Jan 2, 2008
    #23
    i don't need to prove anything. this has been stated numerous times. why are you getting so bent out of shape about this?
    and you said your using an iMac. i'm using a macbook. i'm not techno-savey but could this possibly be why your not seeing your full 3.3gb.
    and at the end of the day.. does it REALLY matter? are you going to sleep any less because of this?
     
  24. macrumorino macrumors regular

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    Dec 25, 2007
    #24
    Just like I thought, you have nothing to contradict what I can observe.

    The rest of your comment is a bit of a waste.
     
  25. LeftoverCrack macrumors member

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    Jan 2, 2008
    #25
    oh my. can you not read all the other people stating this? and the Wiki that states this? what is wrong with you? why are you so set on proving this? what are you trying to accomplish??
    in all 6 of your posts on this entire website you have tried to prove 3gb over 3.3gb. that is the only thing you have said.
    over and over again.
    why? answer me that. WHY?
     

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