4G DDR2 on MBP - rumor

Discussion in 'MacBook Pro' started by Midgetinabikini, Dec 8, 2006.

  1. Midgetinabikini macrumors regular

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    #1
    i heard that apple is going to patch the MBP firmware so there will be option to use 2GX2 memory sticks.

    is that even possiable? the 3G limitation is in the hardware, firmware or the software?

    thank you all,
    have a good night (its around 22:15 in israel)
     
  2. chosenwolf macrumors 6502a

    chosenwolf

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    #2
    Hey, another Israeli on the board! Shalom Chaver! :)

    I did not hear about this, but I do know that OS X is currently limited to recognizing 3GB RAM max (2 + 1 configuration).
     
  3. bearbo macrumors 68000

    bearbo

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    #3
    OS X is by no mean limiting 3GB RAM... mac pro can have 16GB!

    i always thought it's limited by hardware... but i'm not sure
     
  4. AvSRoCkCO1067 macrumors 65816

    AvSRoCkCO1067

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    #4
    OS X isn't limited; Mac Pro can run bundles of Ram - I'm not sure if it's the hardware or software, though, sorry!!! :)

    <beaten by bearbo - walks away in shame...>
     
  5. gr8tfly macrumors 603

    gr8tfly

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    #5
    My understanding is it's a limitation of the chipset and logic board design. I/O address space occupies the upper address range (above 3GB).
     
  6. Scottyk9 macrumors 6502a

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    #6
  7. WildCowboy Administrator/Editor

    WildCowboy

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    #7
    There's nothing firmware updates can do...it's a limitation of the chipset. There are apparent firmware limitations that prevent the MB from booting with more than 2 GB installed, but the 3.2 GB ceiling is imposed by the chipset. You can install 4 GB of RAM, but it only use 3.2 GB for your RAM, as the remainder has to be used for overhead processes that can not otherwise be accommodated due to the 32-bit nature of the chipset.
     
  8. Midgetinabikini thread starter macrumors regular

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    #8
    so if i install 2GX2 the memory will still work in dual-channel?
     
  9. WildCowboy Administrator/Editor

    WildCowboy

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    #9
    I'm not enough of an expert on RAM to know the details, and I don't know the answer to that with the MBPs, but the miniscule speed boost you'd see from running in symmetric dual channel certainly wouldn't be worth the extra $500 for a second 2 GB stick that you couldn't even access. Asymmetric dual channel mode with the 1 GB and 2 GB sticks would be plenty fast.
     
  10. phungy macrumors 68020

    phungy

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  11. Elisha macrumors 6502a

    Elisha

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    #11
    its the limitation of the motherboard which a bios update can fix. which means if Apple releases a firmware update that addresses that issue, you will be able to have 4gb of ram.
    but since MAC does not use a bios but rather EFI, i'm not sure if the Firmware update will even touch that part.
     
  12. gr8tfly macrumors 603

    gr8tfly

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    #12
    Assuming all the required address lines actually reach the "high" 2GB stick. Back to hardware limitation.....
     
  13. robbieduncan Moderator emeritus

    robbieduncan

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    #13
    A BIOS update cannot fix this. It's a 32bit chipset. You cannot make it 64bit using a firmware update.

    A 32bit chipset can only have a total memory space of 4Gb. You cannot use the entire memory space for system RAM. Well you can if you don't want to have any RAM on the graphics card or memory map any peripherals. So it's 3Gb until we reach Santa Rosa.

    End of story.
     
  14. Elisha macrumors 6502a

    Elisha

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    Nov 21, 2006
    #14
    afaik the C2D and the CD Macbook/Pro uses the same chipset. which is a the 945PM/GM so what are you talking about?
    its pretty much the same one that was used on the last batch of Pentium-Ms' which were 32-bit. Nothing to do with 32-bit vs 64-bit
    and they both support 4Gb natively. Apple just limited it thats all.

    here's a comparison link of the chipset in Macbook/Pro:
    http://indigo.intel.com/compare_cpu/showchart.aspx?mmID=22210,145&familyID=7&culture=en-US
     
  15. thejadedmonkey macrumors 604

    thejadedmonkey

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    #15
    Dell's Latitude line goes up to 4 gigs. The Inspiron is only 2 gigs, but if the Latitude can max out at 4 gigs, there's no reason why the PB maxes out at 3 gigs when there's no 64bit chipsets out (at least I think that's right)
     
  16. WildCowboy Administrator/Editor

    WildCowboy

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    #16
    Other PC manufacturers allow you to install 4 GB of RAM, but they are faced with the same limitations as Apple users...only a little over 3 GB is actually addressable. The other vendors have a fine print disclaimer saying that not all RAM over 3 GB may be accessible. Apple has in fact taken the high road by not allowing consumers to waste their money by installing over 3 GB of RAM.
     
  17. Abstract macrumors Penryn

    Abstract

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    #17
    It's hardware. The computer chipset can't actually deal with more than 4 GB of memory.

    Why Apple limited it to 3GB....I don't know. I'm sure it can handle up to 4 GB if it weren't artificially limited. But again, you would only expect around 3.5 GB of the memory to be used as system RAM since we have integrated graphics and other things.
     
  18. Elisha macrumors 6502a

    Elisha

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    #18
    all 4GB is addressable. its just that when the integrated graphics takes its share, it will only show 3.5GB and Apple knows that like PC customers, some people are bound to call into tech support screaming and blaming Apple for scamming them of half a gig or some other logical reason like that.
    but other than that, bios and firmware programming can limit the amount that is addressable by the motherboard. happens all the time in PC motherboards so its no different with MAC since technically it uses the same PC parts now anyway.
     

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