Hello i need some advice, I had a Macbook Pro 15" early 2009 4GB ram. Now i have this MBP 13 i5, but i noticed it is slower and get pauses sometimes when i am doing multitaskig but light stuff like webpages and some apps. I am trying to upgrade to 8GB RAM but i dont know wich is the best option. at amazon.com i could find these 3. Can any one give me an advice about eache one. 1.- Kingston Apple 8GB Kit (2x4GB Modules) 1066MHz DDR3 SODIMM iMac and Macbook Memory (KTA-MB1066K2/8G). Price: $87.99 2.- DDR3 Upgrade for the Apple MacBook Pro 2.3GHz Intel Core i5 (13-inch DDR3) Early-2011 Laptop/Notebook. Price: $81.99 3.- Corsair 8 GB DDR3 Laptop Memory Kit CMSO8GX3M2A1333C9. Price: $74.99 What will be the best option ? and why? Thanks.