The reason is that if you ever wanted to upgrade to 16GB of RAM all youd have to do is purchase another 8GB stick of RAM. If its a board with 4 slots then dual 4GB sticks are superior due to the increased bandwidth. How To Speed Up Your Macbook Pro By Adding More Ram Macbook Pro Ram Upgrade Macbook Pro Tips You wont make any application run faster or better by having more RAM unless all of it is currently in use and your computer is forced to ferry additional data into a cache on your much slower hard drives. . As a general rule the faster the speed the better the performance of RAM. Personally Id get another 8GB or a 4GB at least. For those who dont wish to know the details 2x 4GB RAM is. You can measure RAM capacity in megabytes MB gigabytes GB or terabytes TB. Seasonic S12II 620w 80Plus Bronze. 2x 8GB Corsair Vengeance RGB Pro 3200MHz A2 B2 slot XMP Profile1 default settings CMW16GX4M2C3200C16. For most