I got a memory upgrade for my MacBook Pro and decided to recycle the perfectly good memory into my daughter's MacBook which only has 2MB of RAM. According to Crucial, it should take DDR3 PC3-8500 • CL=7 • Unbuffered • NON-ECC • DDR3-1066. It looks like the RAM that came out of my MBPro is just faster, 12800 instead of 1066. I would not have thought that faster RAM than necessary would have made a difference. At first it gave 3 beeps. Then I tried reseating it and it would not boot at all. I replaced it with the original and all is well. I can purchase the DDR3 - 1066 but I'd like to repurpose this MBPro RAM if possible. By the way, it was only replaced for performance reasons. Not because of any problems. I just wanted things to be faster. I was not having any kind of problems at all. Thanks in advance.