Old Macbook Pro RAM Upgrade Question

[steiney]

Hello All,

I have a Macbook Pro Intel Core 2 Duo, 2.33 GHz, model identifier "A1211". I want to upgrade the RAM to 4 Gigs. I have done some research and keep getting conflicting answers. Some sites say that I can install a matching pair of 2 gig chips,but that only 3 gigs will be addressed. Other sites tell me that while 4 gigs is not officially supported, my computer will accept and recognize it.

Does anyone have any specific knowledge or previous experience on this topic? Any help would be greatly appreciated.

Thank you in advance,

steiney

 

[Hellhammer]

Only 3GB will be recognized because of the chipset

In the developer notes for the MacBook Pro "Core 2 Duo" models -- the MacBook Pro "Core 2 Duo" 2.16 15-Inch, 2.33 15-Inch, and 2.33 17-Inch -- Apple states that:

If you install a 2 GB SO-DIMM in both the bottom and top memory slots of the computer, the About This Mac window and Apple System Profiler will both show that you have 4 GB of SDRAM installed. However, Activity Monitor and other similar applications will reveal that only 3 GB of SDRAM has been addressed for use by the computer.
This applies to the "Late 2006" iMac "Core 2 Duo" models -- the iMac "Core 2 Duo" 2.0 17-Inch, 2.16 20-Inch, and 2.16 24-Inch -- as well, as these systems also officially support a maximum of 3 GB of RAM.

In an superb explanation regarding the 3 GB memory limitation in the MacBook Pro, the always excellent MacFixIt notes that:

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 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. Between 3 GB and 4 GB, however, system memory attempts to occupy space that is already assigned to these functions. For instance, the PCI Express RAM allocation occurs at somewhere around 3.5 GB of RAM and requires 256 MB of RAM. Thus, the virtual space between 3.5 GB of RAM and 3.75 GB of RAM is occupied by PCI Express data. So in a system with 3 GB of RAM, nothing is being wasted because the memory space required by PCI Express is still between 3.5 and 3.75 GB, and the installed system RAM does not violate this space.
The net result is that at least 3 GB of RAM should be fully accessible, while when 4 GB of RAM installed, ~700 MB of of the RAM is overlapping critical system functions, making it non-addressable by the system.
Ultimately, 4 GB of RAM may be installed, but not all RAM in excess of 3 GB can be used due to the possibility of memory "overlap".

For highly technical details, one also may choose to refer to the Intel datasheet for the Mobile Intel 945 Express chipset. Chapter 9, starting on page 317, and in particular pages 324-325 may be of interest.

http://www.everymac.com/systems/app...ore-2-duo-3-gb-memory-limitation-details.html

 

[steiney]

Thanks

Thank you Hellhammer for the quick response.

So basically, other than not being able to use all the RAM beyond the 3 gigs, nothing bad will happen, and the computer will function properly?

steiney

 

[Hellhammer]

Thank you Hellhammer for the quick response.

So basically, other than not being able to use all the RAM beyond the 3 gigs, nothing bad will happen, and the computer will function properly?

steiney

Yeah, 4GB will work fine and "About this Mac" will show 4GB but in Activity Monitor, you will see that only 3GB can be used. Besides, using matched pairs enables dual-channeling which gives ~5% boost

 

[steiney]

Awesome. I didn't know that matched pairs boost performance, although I had read that it is recommended to use matched pairs. I have two 1 gig chips now, so I suppose I won't realize the boost since I'm already getting it. I'll just see roughly 1 gig of increased performance, so to speak.

One more question, if you don't mind: It looks like the brands I have to choose from, at least on Other World Computing (eshop.macsales.com) are the house brand (OWC), Micron and Samsung. Would you recommend one over the others? The price difference between them is very small, so it wouldn't be a big deal to go for the best one (most expensive).

Thanks again!

steiney

 

[Hellhammer]

Awesome. I didn't know that matched pairs boost performance, although I had read that it is recommended to use matched pairs. I have two 1 gig chips now, so I suppose I won't realize the boost since I'm already getting it. I'll just see roughly 1 gig of increased performance, so to speak.

One more question, if you don't mind: It looks like the brands I have to choose from, at least on Other World Computing (eshop.macsales.com) are the house brand (OWC), Micron and Samsung. Would you recommend one over the others? The price difference between them is very small, so it wouldn't be a big deal to go for the best one (most expensive).

Thanks again!

steiney

Just get the cheapest (OWC I think), it's great quality with enormous warranty. You won't notice the difference between the brands so paying more is quite useless

 

[steiney]

Cool

Great! Thanks again. I ordered it today. Can't wait to install it and see the difference.