This has probably been ask before, but I've looked and failed to find any help. So I've got a 2010 MBP 4 Gb ram. I'm thinkin' that I will upgrade to 8 Gb ram later this year. Do I need to get all 8 or can I get 4, since I already have 4 ? Also, is it possible to get 6 instead ? Are there any types of RAM you guys prefer? Lemme know , thanks.