Will PC2 6400/800MHz work with my Early 2008 MacBook (4,1)?

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Will PC2 6400/800MHz work with my Early 2008 MacBook (4,1)?

I am having a problem with upgrading new RAM. I received new RAM sticks and they will not work with my Early 2008 MacBook(4,1) with OS Lion. Here are the stick specs:

Make: Kingston

Product #: KTD-INSP6000C/2G

Speed: PC2-6400/800MHz

Pin count: 200

Other attributes:

SODIMM

DDR2-SDRAM

Unbuffered

Non-ECC

The tech specs from Apple (http://support.apple.com/kb/SP5) say that the bus speed is 800MHz and the how-to-guide to install RAM(http://support.apple.com/kb/ht1651#link3) says that PC2-6400/800MHz should work. However, that how-to-guide lumps 2006-2009 models together. I don't know if all of those models are compatible with PC2-6400 AND PC2-5300 or if that is just the range within the models (e.i. 2006 takes 667MHz while 2009 takes 800MHz). On the Kingston website it lists only Dell products as compatible with the product number I am thinking that is the problem. The how-to-guide does say that 667MHz is the recommended maximum speed for my MacBook model. I just don't know now if 800MHz works for my MacBook. The current RAM sticks I have are the stock PC2-5300/667MHz.

The two Kingston sticks together: Doesn't boot up

One Kingston stick (tried both) with an old stick: Does boot up and work

One Kingston stick (tried both) completely by itself: Doesn't boot up

Here is my frustration, I bought some Kingston sticks (KTA-MB800K2/4G) that are supposed to be compatible with Apple from a company on Amazon and they shipped me the other product number since it is also PC2-6400/800MHz and they are out of stock of the specific product number I ordered. They are saying that the problem is that my computer can't take PC2-6400/800MHz and that the different product number is irrelevant. So, do I need to order different RAM sticks that are a lower speed or should this company ship me the original product number that I ordered?

Thanks!

Posted on Aug 8, 2014 1:00 PM

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Answer 1

Jul 27, 2017 9:40 PM in response to cap_freak

There is a trick to bypass this problem. I bought a set of 2x2GB DDR2 800MHZ chips (less expensive than 667MHZ on eBay) and, after install, the computer wouldn't chime though the optical drive initialized and the sleep light was on. I noticed that the old 1GB 667MHZ chip combined with a 2GB 800MHZ chip worked but everything downscaled to 667MHZ clock speed. Next, I figured the computer must store RAM information upon chip frequency change (or something similar). I installed a 1GB 667MHZ chip and a 2GB 800MHZ chip, restarted, and logged into the user account. Then, I shut down the computer and swapped the 1GB 667MHZ chip for the other 2GB 800MHZ chip and restarted again. Somehow, it worked this time and the computer booted and indicated frequency being 667MHZ.

The problematic computers were both early 2008 MacBooks (4,1).

The steps below explain my workaround solution for making 2 800MHZ chips work:

Install 1 667MHZ chip and install a perspective 2GB 800MHZ chip into the other slot.
Start the computer (login to verify both chips are useable).
Shut down and swap the 667MHZ chip for the other 2GB 800MHZ chip.
Restart the computer (login to verify both chips are useable).

I'm interested to understand more about how the technicalities for how this works. If anyone knows how RAM chips are initialized/used within macs, I welcome your response.

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