Why MacBook Pro Core 2 Duo units are limited to 3 GB RAM

“We previously reported that while the MacBook Pro Core 2 Duo can physically accomodate two 2 GB RAM modules for a total of 4 GB, Apple’s specs list the model as able to recognize a maximum of 3 GB of RAM. Today we have some some additional information regarding why the units can only recognize 3 GB, and the questionable nature of other manufacturers’ claims that their Core 2 Duo-based uportables can address up to 4 GB of RAM,” MacFixIt reports.

“The MacBook Pro Core 2 Duo presumably uses Intel’s 945PM chipset, which can physically handle 4 GB of DDR2 RAM. However, a number of items that must be stored in physical RAM space, and when RAM reaches 4 GB, there is some overlap. In other words, in a 3 GB RAM configuration, there is no overlap with the memory ranges required for certain system functions,” MacFixIt reports.

Full article here.


  1. Of course, duhhh didn’t everyone now that? You stupid people! hehehe

    A 2 gig chip is like 6 hundred and somehtign bucks!!!1 Holy shit!!! like I need 2 of them anyway ” width=”19″ height=”19″ alt=”smile” style=”border:0;” />

  2. ApplePi,

    Unfortunately RAM is very expensive at Apple.

    4 gigs of RAM in my MacPro costs $1200.00 US.

    I bought 4 gigs for my PC gaming rig at an electronics superstore and it was only $250.00.

    Both were 4 single gig sticks…:-(

  3. JerryT, you’re not comparing like memory I think.

    I’ve seen DDR2 PC-5300 for $180 for 1Gb, which would be around $720 for 4Gb. A lot less than Apple are charging for it, sure. But there’s no way you could get 4Gb of Mac Pro compatible memory for $250.

  4. New Mac Book Pro can be upgraded up to 4 GB of RAM.

    2 GB free, 1 GB for Mac OS X and 1 GB for EFI and Trusted Computing to watch what your doing.

    EFI = firmware backdoor to our machines from the internet.

  5. What is interesting here is that the MacBookPro chipset (and presumably that includes the iMac, MB and mini) are going to be limited to 3 GB.

    Even though the OS is capable of using more, the boards won’t let you.

    For some power users who need the mobility / convenience of a laptop this may be an issue

  6. Eric

    There are many reasons for needing more than 3GB of RAM. First, Macs running OS X 10.4 are not usable with only 512MB of RAM in my opinion, and it’s only a default configuration on Apple’s bottom of the barrel offerings. They are very slow and unresponsive. So, 1GB really should be the minimum. And we are only talking about Tiger, we aren’t even considered Leopard yet.

    I have been testing OS X 10.5 Leopard and the situation is even worse. There is a reason why new MBPs and iMacs are coming with a default 1GB of RAM on the “low” end configuration; the reason is simply that Leopard will not run well without at lease 1GB. And keep in mind that is just the OS. Start using several applications at once and you will need 2GB!

    All my Macs are confirgured with 2GB and I am consistantly getting near 100% active memory utilization (using Tiger); and I am not running any special applications either. I’m just a heavy user with lots of stuff open.

    Add Parallels or other Pro applications to the mix and you run out of memory fast; and if you want to run multiple Parallels instances 2GB just isn’t enough. I think 3GB is just a temporary fix. I expect Apple and Intel will have a solution next year to address 4GB on all Macs, including the mini, and will offer that as a BTO option. I also expect Apple to offer their mid to high configurations with a default of 2GB just like they are with the new MacBook Pros.

    Not everyone uses a computer just to do email and internet browsing, and Leopard will have steeper system requirements. 3GB is expensive, but it always is at first. By the end of next year it won’t be. All Macs will come with 1GB or 2GB configurations and a 3GB or 4GB BTO option. And you will you use it.

  7. pog,

    Fry’s in my area had a sale on RAM. It was PC-4200.

    I know you can’t get MacPro RAM at that price. It cost me $1200.00 from Apple to get the same amount.

    It just sucks that they use fully buffered super expensive server type RAM in their work station. Makes sense in the XServe, but FB RAM is slower with more latency than regular DDR2 for most desktop activities.

    But still, I used to spend $5,000 on my design station alone. Now I get a nice design station and a killer game system for about the same amount.

  8. To MacMental: I, for one, *am* running 10.4 with only 512 MB. OK, it’s no speed demon, but I’m running it on a 500 MHz *Pismo*.

    Make sure you’re comparing comparable memory. Yes, memory for the Mac Pro is expensive from Apple. But it’s a far from generic RAM module. When I last checked pricing on Crucial, it was pricey there too.

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