Now and again, Apple’s technical specifications state a maximum amount of RAM that’s not actually correct. It was the case with the iMac G4, and believe it or not, it’s the case with some MacBooks and MacBook Pros. Any 2.2GHz or faster MacBook Pro, and any MacBook made in November 2007 or sooner, actually supports 6GB of RAM, not 4GB! Like all our RAM, the 4GB PC5300 chips carry a lifetime warranty and are guaranteed Mac compatible.
You can tell the speed of your Mac by selecting About This Mac from the Apple menu on the upper-left corner of your screen. If your MacBook Pro is at 2.2GHz or faster, it will accommodate the upgrade, but it’s a bit tougher to tell if your MacBook qualifies. Your MacBook’s serial number is the best way to know for sure whether it can hold 6GB.
Your serial number is very deliberately constructed. The first two characters tell you where the machine was manufactured, the third tells you the year in which it was manufactured, and the fourth and fifth characters tell you the week it was made. Let’s take a hypothetical serial number and dissect it – say, W88231FMYK0. W8 indicates that the machine was made in the Shanghai, China facility. The second 8 indicates the year of manufacture (2008). And the fourth and fifth characters show the week it was made. So, we know from this serial number that the MacBook was made in Shanghai in the 23rd week of 2008.
How does this relate to RAM in your MacBook? Well, MacBooks manufactured in the 48th week or later in 2007 qualify for the 6GB RAM upgrade. When you look at your serial number, you can ignore the first two characters, as it really doesn’t matter where your machine was made. But make sure the third character is 7 followed by 48 or higher. Any MacBook made in 2008 qualifies for the upgrade.
I know your next question already: What about requiring matched pairs of RAM for fastest performance? Well, I’ve never really believed that the average user can tell a difference between a machine with matched pairs and one without. There are several studies out there confirming that the infinitesimal speed loss from not interleaving is more than offset by the availability of more physical memory. Any time you can avoid the use of virtual memory, you’re going to see a big speed boost.
You’ll be excited to know that the unibody laptops all support 6GB as well! We hope to have the PC8500 4GB chips in stock soon.
It’s a bit complicated I know, but our sales team is trained to know whether your machine qualifies. Swing by one of our stores or give a ring and we can help.