I've got 4gb of G-Skill DDR3 1600mhz in 2 sticks of 2gb. Would it be a better idea to go with 2 more sticks of 2gb and get a total of 8gb or would it be fine to stick in 2 4gb sticks and make 12gb? I've never mixed sticks and I know it will take it but I didn't know if there was any unspoken penalty or if it was a no-no to mix 4 gig sticks with 2 gig sticks etc. I doubt I'll ever notice the difference between 8gb and 12gb since I don't really fully utilize my 4gb as-is. Suggestions?