Okay so i currently have the 13 inch mid 2009 model with 2GB of RAM. I bought it in fall of 2009, so Ive had this for a bit. As time went by, I noticed that my overall performance has gotten slower. It takes longer to open applications and I see the spinning circle every so often. I want to upgrade to 4 GB of RAM. Is 4GB noticeably better? BTW, I am a very light user. Most of my RAM goes to Safari and iTunes. Thanks guys.