12 Replies Latest reply: May 27, 2013 5:19 PM by reibel57
Jc61990 Level 1 Level 1
Hello, i have a 15" 2.5GHz MacBook Pro Penryn Early 2008.

It has snow leopard 10.6.6 64-bit installed on it. Currently i am running it with 3GB DDR2 667mhz ram.

I am curious, can i upgrade it to 8GB of DDR2 800MHz ram? Will it be accessible/useable? Wikipedia says i can only upgrade to 6GB, but i think thats due to 10.5, 10.6 being x64 i would assume it should be able to address 8GB of memory. Thanks!

Macbook Pro 4,1 and MacBook 5,2, Mac OS X (10.6.6), MBP 2.5GHz; MB 2.13GHz
  • CMCSK Level 6 Level 6
    can i upgrade it to 8GB of DDR2 800MHz ram?

    Download Mactracker. This utility will tell you everything you need to know about your Macbook Pro. You can download this utility from Macupdate and Cnet Mac Downloads.
  • Allan Jones Level 7 Level 7
    And MacTracker says your max is 6GB RAM (1 x 4GB and 1 x 2GB). Faster RAM will simply clock back to the system's speed, but sticking with 667 may make for better stability.
  • gbullman Level 2 Level 2
    I looked up your machine in Mac Tracker and it can only recognize a max of 6 GB RAM. This is a hardware limit, not an OS limit. I seem to remember reading where the restriction came from some time ago but don't remember exactly what it is. Think it has something to do with the Intel Chip set used in those machines (my late 2007 MBP can see 6 Gig of RAM as well).
  • Jc61990 Level 1 Level 1
    Hmm, well even if i go with 6GB ram, i would still rather go with 800MHz being that the systembus is 800MHz. i have 4GB 800Mhz in my White MacBook tied with a hybrid solid state hard drive. thing is fast as ****. kinda upsetting that my macbook is faster than my pro.

    i can deal with 6GB, i mean 8 is kinda overkill but if i was able to do it, why the **** not lol.

    i have 3GB 667mhz and a 5200rpm hard drive in my pro, i can definitely see it choking some times, the ram wont make much of a difference but i know for a fact the hard drive will.
  • gbullman Level 2 Level 2
    Agreed the system bus is 800 MHz, but all information I have is that these machines take PC-5300 RAM which is 667 MHz.

    Here is available memory for these machines from [Other World Computing|http://eshop.macsales.com/shop/memory/MacBook/Pro/Core2>

    You are correct that the hard drive is the slowest link in the chain. I've always had a 7200 RPM drive to get as much as possible out of this machine. By the way I run 2 Windows XP VMs plus a bunch of Mac apps with my 4 Gig of RAM and it does fine.
  • Jc61990 Level 1 Level 1
    oh no doubt it runs fine.
    My white macbook runs amazing with 4gb ram and a hybrid solid state hard drive.

    Also since my macbook has 4gb of 800mhz ram in it, ill try putting it in this computer see how it runs, if i actually see it run slower since its supposed to take 667. ill order 6gb of 667. but i would also think all these limitations should have been lifted with snow leopard.
  • Jc61990 Level 1 Level 1
    Well, i guess i just answered my own question.. I installed the 4gb of 800mhz ram i have in my macbook, i put it in my macbook pro, and it didnt boot.. the light on the screen release came on, but the LCD stayed black. swapped the ram back and it booted right up.. guess im going for 667mhz ram when i order ram...

    Thanks for the help!!
  • letsgo1776 Level 1 Level 1

    I know this is an old thread but I have something to add.


    I upgraded my early 2008 Macbook Pro 4,1 15 inch to 6GB (4+2).  I then decided to take a chance and order another matching 4GB stick of memory.  It works.  I have now have 8GB or RAM.....  Running Lion 10.7.3.


    I used 2 (4GB) Mushkin PC2-5300 SODIMM.

  • letsgo1776 Level 1 Level 1

    Upon further review... The ruling on the field stands....


    It was true that I was able to boot up with 8GB of RAM.... However,  when attempting to do anything that required large amounts of memory (i.e. run vmware) the CPU would peg out near 100%.  I then replaced one of the 4GB with the 2GB, and the CPU did not peg out.... 


    So I am going to stay at 6GB (4GB+2GB) for now....

  • RodWall5 Level 1 Level 1

    Thanks for that info. I have the same Mac as you, but the 17 inch. Now, I have 4Gb of Ram and I was looking if this Mac would support more than 4Gb.


    I guess I'm going for the 6Gb.

  • engana Level 1 Level 1

    I had exactly the same issue... 2x4Gb the all RAM was recognized and the system runned smoothly until a certain point... when allocating more  than 4Gb the CPU goes wild on 100% and the computer turns useless.

    Downgraded to 6GB and everything is now fine. Did you found any solution to this? It's a rather silly problem..

  • reibel57 Level 1 Level 1

    I know this is a old issue, but I was considering adding a 4Gb memory card to step up to 6Gb for my 2008 Macbook Pro. My question is, does it matter what slot you put the 4GB into and is there a preferable name brand?