6GB in MacBook (Pro); Yes it works. - 8GB... well...

Discussion in 'MacBook Pro' started by ayeying, Oct 2, 2008.

  1. fireloss macrumors member

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    #126
    Well, 4 and 6GB are reported to work on Leopard, and 8GB is reported to work on Snow Leopard. So, I think it's not a hardware limitation.
     
  2. alphaod macrumors Core

    alphaod

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    #127
    I'll have to confirm that too. I just tested that Windows will not boot with more than 4GB...
     
  3. Cave Man macrumors 604

    Cave Man

    #128
    That's peculiar. I can VMWare or Boot Camp with 8 gb installed. I'm only using 32-bit Win XP.
     
  4. ayeying thread starter macrumors 601

    ayeying

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    #129
    You're asking the wrong person on why 8GB doesn't work since I said, I don't have 8GB to test with. However, the other users seems to have some trouble with 8GB especially in executing programs that are memory hogs.

    Not entirely. The system drivers are different also. It could be just as simple as OSX saying, hey, this is a MBP, not MP, I'm going to limit you. Its not impossible. Furthermore, firmware could also limit ram execution somewhat. We just don't know.

    I don't think anyone has said 8GB works in Snow Leopard. I tested 6GB in Snow Leopard because thats all I have.

    I was able to boot 6GB in 32-bit Windows XP. However, due to the 32-bit, I was only able to read 2.98GB.
     
  5. alphaod macrumors Core

    alphaod

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    #130
    I even have 64-bit Vista!

    Anyways, I decided to RMA the RAM; NewEgg is waving 15% restocking and paying for return shipping. What a great company.

    Actually I RMA'd one stick; going to keep the other for now, unless someone wants to buy it.
     
  6. alphaod macrumors Core

    alphaod

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    #131
    I just tested it out this morning and I found that if I had my 4GB on the outside slot and the 2GB on the inside slot, the computer wouldn't POST. It would just beep during boot to indicate memory error. Immediately switch the RAM position alleviates the issues. And yes 6GB works flawlessly.

    I returned my other 4GB, so I'm not longer able to test the "maximum" configuration.
     
  7. DaveTheGrey macrumors 6502a

    DaveTheGrey

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    #132
    anyone noticed any difference in temperatures with 8GB compared to 2 or 4GB?
     
  8. mrwizardno2 macrumors 6502a

    mrwizardno2

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    #133
    This is very interesting. I can't wait to see how this pans out.
     
  9. ayeying thread starter macrumors 601

    ayeying

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    #134
    I see a 1 deg C increase... which is nothing
     
  10. alphaod macrumors Core

    alphaod

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    #135
    I came back from the store and as usual they gave me the stripped down explanation thinking I'm totally hardware ignorant. *sigh* Told me the computer is bottlenecked; yeah right.

    However I do know that on certain desktop 965 boards, the memory can only run a 533MHz when you run 8GB, but I doubt that would cause this tremendous slowdown.
     
  11. Eidorian macrumors Penryn

    Eidorian

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    #136
    I hope you didn't expect much more then that. ;)
     
  12. alphaod macrumors Core

    alphaod

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    #137
    No.

    The main reason I went was because my Airport Express broke again for the 4th time in 4 months.
     
  13. KingYaba macrumors 68040

    KingYaba

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    #138
    So, did anyone run a hardware test with 8 gb installed? Either the TechTool utility or Apple's test on their OS X disks?
     
  14. ayeying thread starter macrumors 601

    ayeying

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    #139
    Actually, thats not a bad idea. I Don;'t have 8GB but I'll test with 6GB to see if theres anything that pops up. Um.. whats the command again? hold D during boot?
     
  15. Cave Man macrumors 604

    Cave Man

    #140
    Is there any chance that the vRAM of the video card is confusing the system? I mean, I have 256 mb card - is it possible that the OS is seeing that as a total of 8.256 gb and causing problems? Probably grasping at straws here, but it might be nice to find someone with a SR MacBook to test the 8 gigs with.
     
  16. Eidorian macrumors Penryn

    Eidorian

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  17. alphaod macrumors Core

    alphaod

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    #142
    That is possible; the VRAM is causing the computer to think it has more RAM than it can support. A very plausible theory. Now the quest is to find 3GB chips to test that theory. Or test it on a MB.

    However, the question would be how Thinkpads and such support 8GB of RAM when they have dedicated GPUs with lots of VRAM and their specs only support 8GB as well?
     
  18. aleksandra. macrumors 6502a

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    #143
    Is PAE enabled by default in MBP? If it isn't, and Santa Rosa supports only up to 8GB of address space and no more, then like earlier platforms using only ~3GB of RAM, it might effectively use <8GB... Just my thoughts on it.
     
  19. fireloss macrumors member

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    #144
  20. alphaod macrumors Core

    alphaod

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    #145
  21. kobefan234 macrumors 6502

    kobefan234

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  22. darwinian macrumors 6502a

    darwinian

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    #147
    Very interesting thread. I've recently been using my MBP for my work more than my MP for various reasons, and I've noticed that the slower memory bus and perhaps less memory has meant that my MBP writes to swap a lot more than I'd like, even with 4 GB of memory. Identical operations on the MP (2.0 GHz, 6 GB) run considerably slower on the MBP (2.2 GHz, 4 GB), presumably due to the bus speed. Increasing memory to 6 GB won't change its bus speed, obviously, but will I see fewer page outs? Primarily I am not writing any contiguous piece of memory that's larger than about 2 GB.
     
  23. fireloss macrumors member

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    #148
    http://www.appleinsider.com/articles/08/08/26/road_to_mac_os_x_10_6_snow_leopard_64_bits.html&page=3

    "Currently, Mac OS X Leopard hosts both 32-bit and 64-bit apps on top of a 32-bit kernel (below). Using PAE, the 32-bit kernel can address 32GB of RAM in the Mac Pro and Xserve; Apple's consumer machines only support 4GB RAM, but unlike 32-bit operating systems they can use the entire 4GB (with appropriate hardware support). Leopard's 32-bit kernel enabled Apple to ship 64-bit development tools to give coders the ability to build applications that can work with huge data sets in a 64-bit virtual memory space (and port over existing 64-bit code), without also requiring an immediate upgrade to all of Mac OS X's drivers and other kernel-level extensions. That transition will happen with Snow Leopard."

    :)
     
  24. kobefan234 macrumors 6502

    kobefan234

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  25. ayeying thread starter macrumors 601

    ayeying

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    #150
    Depends on what you do. Average user who just surf the net and chat will see 0 difference. The past day, I've been running in Snow Leopard and it is EXTREMELY faster when it comes to virtual machines. I am running Vista on a 3GB dedicated Boot Camp partition in VMWare Fusion 2 and it is a breeze when you don't have swap kicking in.
     

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