3 Replies Latest reply: Jan 29, 2009 9:26 AM by snatchmo
snatchmo Level 1 (0 points)
I'm attempting to upgrade my ram from 2GB to 4GB on an early 2008, 2.5GHz, 6MB L2, MBP. I've purchased 2x2GB, PC-5300, DDR2-667MHz modules and attempted to install them. After installing the two modules my MBP would not boot. I contacted the manufacturer of the ram and they suggested attempting to install one 2 GB module and one of the original 1GB modules. This configuration functions properly. Both 2GB modules have been verified as functional when used with one of the original 1GB modules and have been tried in both slots. Any ideas as to why my MBP will not boot with more than 3GB of memory ?

MBP 4.1, Mac OS X (10.5.6)
  • stedman1 Level 9 (67,880 points)
    Hi snatchmo: Your description of the issue sounds suspiciously like an issue with incorrect RAM. There have been quite a few posts on here that are like yours. Work fine with one original stick of RAM and one new one, but will not boot with 2 new sticks. The common thread seems to be RAM that is rated at 800mHz. Is your RAM rated to work at 800mHz, as well as 667mHz? If you have a model/part number on the RAM we may be able check it's specs.

    Hope this helps
  • snatchmo Level 1 (0 points)
    Hi Stedman,

    The memory I have is mfg'd or perhaps better stated, marketed, by Centon, pn. 2GB667LT, and has no reference to 800MHz. I'm slogging my way through the posts and have yet to encounter an issue exactly like mine yet, many similar though.

    Thanks for respondin'.
  • snatchmo Level 1 (0 points)
    Hi again,

    Response from Centon suggests this: "MacBook Pro EFI Firmware Update 1.6 "


    I don't think it applies.

    Model Name: MacBook Pro
    Model Identifier: MacBookPro4,1
    Processor Name: Intel Core 2 Duo
    Processor Speed: 2.5 GHz
    Number Of Processors: 1
    Total Number Of Cores: 2
    L2 Cache: 6 MB
    Memory: 3 GB
    Bus Speed: 800 MHz
    Boot ROM Version: MBP41.00C1.B00
    SMC Version: 1.28f1

    Still at a loss as to why both modules won't work together. Centon advises that system should boot with only one module installed, I'll give it a try.

    Many thanks