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MBP C2D max RAM..?
- Thread starter ieko
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Welcome to MR -- Searching is good, this has been covered many times
3 Gb is the limit. It is a limitation of the hardware memory controller on that motherboard.
3gb is the max. If you put any more in it would just not be used. It would be just a waste.
The Stig
This doesn't seem to be a limitation of the chipset for that board. The Intel 945PM supports 4GB RAM, with all of it addressable (see http://www.intel.com/products/chipsets/945pm/index.htm
So what is it that Apple does to the Macbook Pro to make it support only 3GB?
Damo
I have asked this question in the past and never got a proper answer, or at least one i understood.
The reason they only officially support 3gb is because the chipset maps certain address above the 3gb range as virtual addresses for other critical systems (such as the PCI-E bus). This means that our user side OS'es can't make memory into that range, therefore would essentially be useless to us.
It is in fact true that you can put in 4gb and the system will run. However almost 700mb of the space above 3gb can not be used (I believe 3.3gb and above are used for virtual memory space).
So Apple in order to remain more "honest" has limited the MBP to 3gb of ram.
Reference: http://news.softpedia.com/news/MacBook-Pro-Core-2-Duo-Limitations-39006.shtml
That's well and good, but as per the link i posted, intel states that a full 4GB of RAM is addressable on that chipset. If that is not true, it would be cause for a lawsuit for anyone who wishes to take it up.
I still think this must be a Mac hardware specific issue, not just them being honest about an inherent flaw.
Damo
What flaw? The chipset has a address limitation of 4 GB. Some of that address space has to be reserved for mapping I/O devices, some of which also have on-board memory. Get it? Nobody's lying to you, nobody cheated you and this isn't a conspiracy to screw you out of your money. It's a limitation of the existing chipset, and Apple plainly stated a 3 GB max memory limit.
I think you're taking what intel is saying about "addressability" too literally. Addressable doesn't necessarily mean its usable. The memory is in fact addressable. Its just the OS can't use it because when the OS needs to address the PCI-E bus, it uses the same memory addresses.
As for lawsuits... well sorry but look at page 319 for the Intel Mobile 945 chipset family. It specifically shows there is allocation in the upper memory ranges for the PCI Memory address range. Unless I'm misunderstanding, Intel knows about this limitation.
And the reason why chipsets currently struggle to support more than 4gb of memory (from what I understand) is the limitation of a 32-bit architecture. Which is one of the reason why we're seeing a push for 64-bit processors.
Well, it can't be a Mac hardware specific issue since it obviously affects HP notebooks as well.
You know, people should really read their posts before they submit, otherwise they end up sounding like arrogant jerks. daveL, I can't see in my post where I stated that someone had lied or cheated or even created a conspiracy. Can you? I was merely asking a question for something that wasn't clear. Intel's website says 4GB is addressable, HP states on their site that laptops using this chipset support up to 4GB, as do many others. In fact, the only evidence anyone has given me that 4GB is not supported relates directly Mac's. So not unreasonable to ask the question, at least I don't think so.
Get it?
Damo
Okay, well that makes a little bit more sense. If addressable doesn't mean useable, then that does make things a bit clearer. Thanks for your answer.
But since you mentioned lawsuits, Intel could still be left liable, even if all the information is provided. I haven't read page 319, I imagine that most people haven't. If it's not reasonable to expect that a person would've read it, then the most available information will be taken as what people can expect of the product.
Damo