We normally recommend not going for anything smaller than an 8 GB dimm. Our reasoning behind this is that most people would want to go for a duel channel setup and 16 GB of ram. Using 8 GB dimms allows you to upgrade to 32 GB latter on. We have tested different ram levels and the performance gain going from 16 GB to 32 GB isn’t that big but some applications are starting to take advantage of higher levels of ram. If you are running a quad channel setup with 8 GB dimms you have the option to go all the way up to 64 GB.