Works great in late 2008-2009 Macbook: Crucial 8GB Kit (4GBx2) DDR3 1066 MT/s (PC3-8500) CL7 SODIMM 204-Pin Notebook Memory Modules

They said it couldn't be done, and they were wrong. I found instructions on the web to confirm my EFI firmware was up to date, and then just installed the DIMMs. This kit works great in my late-2008 Macbook Pro 15" and 8GB memory makes a huge differences for my multitasking.

The Crucial Memory works great - no flaws, errors, or anything but extremely fast performance. I wanted this kit because I use my iMac to do a lot of work with videos and to run a Windows 7 virtual machine. Everything runs a lot faster. The Windows 7 machine performs wonderfully with the 4GB I've assigned to it; it boots quicker and loads applications as fast as it would from a machine running Win7 natively.

• Module Size - 8GB kit (4GBx2)
• Package - 204-pin SODIMM
• Feature - DDR3 PC3-8500
• Specs - DDR3 PC3-8500; CL=7; Unbuffered; NON-ECC; DDR3-1066; 1.5V; 512Meg x 64

Go faster and further with a notebook or netbook memory upgrade from Crucial. We've got quality SODIMM memory for mobile systems. And because a memory upgrade is one of the easiest, most affordable ways to improve system performance, it's the ideal solution for on-the-go users. If you count on your netbook or notebook, count on memory from Crucial. Crucial is a key brand in the Lexar Media family of products.

The best thing is that switching between Windows and Mac OSX is now very smooth, no more waiting or delays, it's just like having Windows running as another app on the desktop.  I can now easily work with photoshop without seeing the rainbow circling on my screen.

To be sure which one of the two memories you should buy, open your macbook and see what you have first, PC3-8500 chip or PC3-10600 chip and buy accordingly. If your macbook has PC3-8500 (Early 2009 I guess) then PC3-10600 will not work and will freeze your laptop while rebooting.

Installation is very simple, make sure you don't loose your macbook screws though as they are really small. Snap-out your old memory and snap-in the new ones. Close the cover and there you go !!!  This Crucial 8GB Kit (4GBx2) DDR3 1066 MT/s (PC3-8500) upgrade is worth it, and is much cheaper than Apple's upgrade, and also Amazon sells it at a far better price than if you buy directly from the manufacturer. Gotta love Amazon !