I just recently upgraded my Intel Core 2 Duo MBP that I bought in March from 2GB to 4GB and my friend said he would like to purchase my old memory. He has a Core Duo MBP currently with 512 MB from about 2 years ago. Would the memory I just took out of my MBP work with his MBP or would there be issues? I'm not too knowledgeable about memory and the differences from computer to computer as this was the first time I have ever upgraded my memory. Any info on this would be a big help. If more info is needed please let me know. Thank you in advance.