I have been looking around and trying to find the answer, but I still have a question that I need to ask. If it has already been explained I am sorry. I want to upgrade my macbook's harddrive and I know it takes the 2.5 SATA drives. The problem I am having is that when I was researching prices there were numbers that are confusing me like SATA-300 and SATA-150. Do I need to be concered with those numbers or is there a particular drive that I need to get. Thank you very much for your time.