C2D Napa...64-Bit Ready or not?

Discussion in 'Buying Tips and Advice' started by netdog, Jun 13, 2007.

  1. netdog macrumors 603

    netdog

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    #1
    Not that I am going to upgrade, but when I bought a C2D Napa machine, everyone here insisted that this was finally the true 64-bit Mac that would support Leopard best. Now I am reading that SR is the first true 64-bit capable Mac.

    Please, if somebody who really knows the ins and outs could tell me what gives, and what the real world advantages of SR are in terms of 64-bit performance and capabilities, I would really appreciate it! :D
     
  2. EricNau Moderator emeritus

    EricNau

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    #2
    Both are Core 2 chips, and yes, I believe both are 64 bit.
     
  3. daneoni macrumors G4

    daneoni

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    #3
    The only difference is that SR can address more than the 3GB RAM Napa does. Both (with Core 2 Duo chips) are still 64-Bit ready.....top to bottom.
     
  4. netdog thread starter macrumors 603

    netdog

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  5. roland.g macrumors 603

    roland.g

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    #5
    Yes as I understand it, 64 bit can address more than 4GB of RAM, but does not require it. So a 64 bit CPU works with Leopard, whether Merom or Penryn, and on a Napa or Santa Rosa chipset. And SR allows for more than 4GB of RAM, so technically when there are 4GB sticks, you could have 8GB total in a 2 slot SR machine like a new MBP. Of course the Xeon Mac Pros have had more than 4GB capacity since their inception.
     
  6. booksacool1 macrumors 6502

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    #6
    Yeah there was a chipset limitation in Napa. 3-3.2gb tended to be the max. Its a bit of a problem because most people probably have their Napa MBP's with 2gb and will be annoyed when they find out they have virtually no upgrade options.

    As for 64bit, both Napa and SR support it provided you have a Merom/C2D cpu. The original Core Duo's were not 64bit (even though they are part of Napa).
     
  7. gaelan macrumors regular

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    Oct 11, 2005
    #7
    do they make 1.5GB RAM sticks? i figure 2GB is sufficient for most iMacs, but what is the best way to max out a napa machine? 2 - 1GB sticks or 2-2GB sticks?
     
  8. roland.g macrumors 603

    roland.g

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    #8
    1x1GB and 1x2GB.
     
  9. gaelan macrumors regular

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    #9
    so what's the best way to max out the RAM in the current iMac? 2 one gig sticks or 2 two gig sticks OR a mix of both to total 3 gigs? i understand the limit on napa is 3.2, so it seems silly to waste the other .8 of RAM
     
  10. roland.g macrumors 603

    roland.g

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    #10
    a mix. one 1GB and one 2GB. That's what Apple does if you configure for 3. Don't try to get that extra .2 and don't worry about matched pairs, the advantage of 3GB vs. 2GB outweighs the disadvantage of having different size sticks. The performance gain of matched pairs is minimal.
     
  11. gaelan macrumors regular

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    Oct 11, 2005
    #11
    cool...thanks.

    so what kind of performance advantage can the average end user expect from frontside bus speeds of 800 MT/s vs a 667 MT/s? I pulled these numbers from the Wiki entry comparing Napa and Santa Rosa.
     
  12. flopticalcube macrumors G4

    flopticalcube

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    #12
    Money no object, the best solution is 2 X 2GB matched pair but you will waste almost half of one stick for a very small gain in performance.
     
  13. flopticalcube macrumors G4

    flopticalcube

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    #13
    Less than the 20% implied by the increase. IIRC, real world tests showed an increase of about 9%.
     

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