I'm looking to upgrade the ram in my new laptop, but I seem to be getting mixed messages about what I can add. I found an online manual that states I can max out at 2x4GB sticks, however the crucial website says I can fit up to 2x8GB sticks. Which should I stick with? Also, if I go the 2x4GB, can I just purchase one more 4gb stick, or do I have to get 2 new ones? Can I just match what I have now (1x4gb), and if so, what brand/speed etc do I need?