I bought a refurbished white macbook sometime during aug 2008. It has the following configuration - 2.1GHz with 1GB RAM. I'd like to upgrade to 4GB and when i did Apple menu - > about this mac, I got the following : Processor 2.1GHz Intel Core 2 Duo Memory 1 GB 667 MHz DDR2 SDRAM So when I'm buying a 2*2GB cards, what are the specs that I should look out for ? Will a 800 MHz fit my mac ? Coz the bus speed is mentioned as 800 MHz.. I'm inclined to buying the kingston memory card - http://www.newegg.com/Product/Product.aspx?Item=N82E16820134370 Plz let me know if I'm making the right decision.. and also whether 800MHz is a good idea.. Thanks a lot..