I'm getting a new 27-inch iMac with the minimum RAM. I'm looking at getting this to upgrade: http://www.bhphotovideo.com/c/search?Ntt=CR8S312800MQ&N=0&InitialSearch=yes&sts=ma&Top+Nav-Search= 1. Is this a good price? 2. Is this the best configuration, four sticks of 8GB as opposed to two sticks of 16GB? Thanks.