Upgrading Penryn MBP to 6GB RAM and having problems - need guru help!

Discussion in 'MacBook Pro' started by micsaund, Jul 2, 2009.

  1. micsaund macrumors 6502

    micsaund

    Joined:
    May 31, 2004
    Location:
    Colorado, USA
    #1
    Hi all,

    A friend of mine at work, who has the same MBP as I do, recently added a 4GB stick in with a 2GB and it works great, as many others have found-out. It's a Penryn 2.5GHz 4,1 version.

    So, I ordered a Crucial 4GB stick from Newegg which arrived today, since the price is down quite a bit.

    However, when I add the 4GB stick in with one of my 2GB sticks which I've been using for over a year, I get problems.

    Sometimes I get the EFI BIOS beeps (3 I think -- corresponding to memory) and other times when I power-on, the screen just stays black and I hear fans and DVD drive going, but nothing ever happens.

    If I pull either one of the sticks, things work normally.

    I've swapped the 4 and 2 sticks into the top/bottom slots, and also tried both of the 2GB sticks I had already with the new 4GB.

    I ran memtest86+ on the new 4GB by itself, and it did not show problems (I'm actually writing this while running on this new stick by itself). The same with both 2GB sticks, by themselves or together.

    However, the one difference I see in memtest is that the 4GB is 5-5-5-14 and the 2GB sticks are 4-4-4-14.

    Is the Mac not smart enough to choose the slower setting and run them both at that speed? Do you think this is why I'm getting nothing but black screens and no ability to even boot? Is there any way to manually set the timings like I'd do on a normal x86 machine in the BIOS?

    Any other ideas or suggestions?

    I really don't want to send the RAM back to newegg, as by the time I pay a restocking fee and shipping both directions, I'm flushing $30 or more down the toilet, but if the stick just won't cooperate with my existing 2GB stick(s) then I guess I don't have a choice. I'm hoping someone here knows how to set the timings at a system level if that's the problem.

    Thanks,
    Mike
     
  2. micsaund thread starter macrumors 6502

    micsaund

    Joined:
    May 31, 2004
    Location:
    Colorado, USA
    #2
    UPDATE:

    Allright, I broke-out my hardcore geek-fu and edited the SPD EEPROM settings on the 4-4-4-14 2GB sticks to set them to 5-5-5-14, which brings them inline with the new 4GB stick.

    Boots just fine now. I'm running memtest86+ 2.11 now and it shows 6GB at 5-5-5-14 and no errors so far.

    I'll take it "easy" with this config for a while to see if it's reliable. I can't believe that Apple would make the EFI/BIOS/whatever so inflexible as to not simply use the slower settings from two different SO-DIMMs.

    Mike
     

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