After reading Apple dox and lots of postings, I am still confused on how to get the appropriate amount of memory and combine it with riser placement for best bandwidth. I would to buy 4G modules and end up with at least 10 Gb instead of the current stock 2 Gb. So I ordered 8Gb and am now confused Ideally, can I simply move both 1Gb x 2 to the lower riser and install the 4Gb x 2 in the upper riser and have the best bandwidth? Should I purchase/match 8Gb more and put those in the lower riser and toss the stock 2Gb? Am I not going to notice any of this anyways and just be happy I'm feeding my 2 Virtual Machines more memory?