New Macbook Pro RAM expansion

Discussion in 'MacBook Pro' started by hellisforheroes, Oct 29, 2008.

  1. hellisforheroes macrumors newbie

    hellisforheroes

    Joined:
    Sep 5, 2008
    #1
    Want to add some RAM to my new (and very very nice) Macbook Pro. It says that it only supports 4GB of RAM on the specs but does this mean that you can install an extra 4GB or just 2 (as it already comes with 2GB already)
    The Apple store seems to be selling 4GB kits which is a little confusing as that would mean that it can actually support 6GB - And this is all getting a little confusing!!
    Can anyone shed some light.
     
  2. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #2
    You can replace your 2x1GB RAM sticks (2GB) with 2x2GB RAM sticks (4GB).
     
  3. nptski macrumors member

    Joined:
    Jul 22, 2002
    Location:
    newport beach, ca
    #3
    Be careful, I have had nothing but problems and had to take the 4g upgrade memory out and put the stock memory back in. Lots of freezing up problems.
     
  4. Spanky Deluxe macrumors 601

    Spanky Deluxe

    Joined:
    Mar 17, 2005
    Location:
    London, UK
    #4
    The 4GB memory kits from Apple are for 2x2GB to replace the 2x1GB in your machine already.
     
  5. HawaiiMacAddict macrumors 6502a

    Joined:
    Dec 28, 2006
    Location:
    On one of my Macs of course
    #5
    Aloha hellisforheroes,

    Interesting account name :D Apparently, the logic board and chipset can accept up to 8GB RAM, indicating that the 6GB limitation is most likely firmware based. PC laptops with the same CPU and chipsets indicate up to 8GB RAM capacity, so the general consensus is that Apple will provide an update to the new MacBook/MacBook Pro laptops such that up to 8GB RAM will be recognized and completely utilized by the system.

    HawaiiMacAddict
     
  6. Minimoose 360 macrumors 65816

    Minimoose 360

    Joined:
    Jul 7, 2008
    Location:
    NY
    #6
    Assuming you have an older MBP, they support UP to 4GB...meaning if you wanted 4GB, you would have to take the two 1GB sticks and replace them with 2GB sticks.

    The new Macbook Pro supports up to 8GB when the software update is released. In case anyone has been living under a rock. ;]
     
  7. hellisforheroes thread starter macrumors newbie

    hellisforheroes

    Joined:
    Sep 5, 2008
    #7
    Great, thanks. Didn't realise that the built in memory is in the slots already (because when i updated my ibook there was just an empty slot.) That all makes sense now. Cheers.
     
  8. hellisforheroes thread starter macrumors newbie

    hellisforheroes

    Joined:
    Sep 5, 2008
    #8
    Guess that means you can then use 2 x 4GB RAM modules (which seem to be a little harder to find) when and if.
     
  9. hellisforheroes thread starter macrumors newbie

    hellisforheroes

    Joined:
    Sep 5, 2008
    #9
    Jolly good evening Hawaiimacaddict, as we would say here in sunny England.
     
  10. barefeats macrumors 65816

    barefeats

    Joined:
    Jul 6, 2000
    #10
    6GB works; 8GB don't

    I installed two 4GB modules in my 'late 08' MBP 2.8 today. As with the 'early 2008' MBP, it will see and use all 8GB for apps, but goes into molasses mode when you exceed 4GB of real memory usage. And it won't release the memory even if you can get the "greedy" app(s) to quit.

    But when I put one 4G + one 2G module for a total of 6GB, it is happy as a clam. Everything runs fast and the full 6GB is accessible. And it releases the memory when you quit the app(s).

    Now the 6GB config means you lose the dual-channel support -- no matching modules. I plan to run some memory benchmarks to see just how much is lost but I bet you'll need a stopwatch to tell the difference.
     
  11. sparkie7 macrumors 68000

    sparkie7

    Joined:
    Oct 17, 2008
    #11
    yeh, cool. keep us posted :D:p:D
     
  12. Jimbo99 macrumors newbie

    Joined:
    Oct 26, 2008
    Location:
    Los Angeles
    #12
    You may actually end up with dual-channel support for the 2GB module and the first 2GB of the 4GB module. At least, that's the way it works with the Intel Centrino 2 chipset. But I'm not familiar with the details of the new NVidia chipset, and I'm not sure whether such detailed information is yet available regarding its dual-channel support.
     
  13. Spanky Deluxe macrumors 601

    Spanky Deluxe

    Joined:
    Mar 17, 2005
    Location:
    London, UK
    #13
    I've never heard that about the Intel Centrino 2 chipset, I'm sure you lose dual channel when using mismatched pairs.
     
  14. Jimbo99 macrumors newbie

    Joined:
    Oct 26, 2008
    Location:
    Los Angeles
    #14
    It's called Flex Memory mode:

    from p.60 of:
    Mobile Intel® 4 Series Express Chipset Family
    Datasheet
    August 2008
    http://www.intel.com/assets/PDF/datasheet/320122.pdf

    5.2.1.1 Intel Flex Memory Technology (Dual-Channel Interleaved Mode with Unequal Memory Population)

    The GMCH supports Interleaved addressing in dual-channel memory configurations even when the two channels have unequal amounts of memory populated. This is called Intel Flex Memory Technology.

    Intel Flex Memory Technology provides higher performance with different sized channel populations than Asymmetric mode (where no interleaving is used) by allowing some interleaving.

    The memory addresses up to the twice the size of the smaller SO-DIMM are Interleaved on a 64-B boundary using address Bit 6 (including any XOR-ing already used in Interleaved mode). Above this, the rest of the address space is assigned to the remaining memory in the larger channel. Figure 7 shows various configurations of memory populations.
     
  15. b3studios macrumors newbie

    Joined:
    Jan 23, 2006
    #15
    I had the same problem. Had a stock 2.4Ghz new MBP and upgraded the RAM to 4GB using Crucial sticks.
    I had freezes as well as waking from sleep problems.
    Tried 4GB G. Skill sticks and had the same problem.
    No issues with stock RAM.

    Returned the machine and got the 2.53Ghz model with 4GB installed (and larger HDD, L2, etc)
     
  16. Adam Ierymenko macrumors newbie

    Joined:
    Mar 7, 2008
    #16
    http://forum.insanelymac.com/index.php?showtopic=99891

    Try using the maxmem flag with 6144 with the two 4gb sticks. This should tell the OS to only use 6144 of the available 8194. You could then remove the option when the software/firmware update comes out. You could leave the two sticks in that way and just use 6144 of it until the update is ready, and you'd still have dual-channel.

    If the option kills your ability to boot, just reset nvram. (Google how to reset nvram... it's a key combination on boot but I forget.)

    This requires a bit of command line hacking... :)
     
  17. !eon macrumors newbie

    Joined:
    Oct 16, 2008
    #17
    I regret that I didn't upgrade to 4GB ram when ordered my new Macbook Pro, now I'm stuck with the stock 2GB. I was thinking to upgrade 4GB DDR3 by myself, but I heard there is freeze problem with the 2x2GB rams from Cruical and G. Skill, Apple.com has 4GB ram for $300. What should I do? Thanks in advance.
     

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