Answering this myself here in case anyone needs to know in the future :) I called Videoguys and they recommend 2 X 8GB RAM. In the future, should you want to improve performance, you can then add 2 X 8GB RAM to go into the last two RAM slots. No matter what, RAM needs to be added in equal pairs. If you... (read more)

[quote user="videoguy"] RAM: 8GB of RAM is the bare minimum. As a rule of thumb, we recommend 3GB of RAM per CPU core, so for best results with an i7 quad core CPU, get 12GB (triple channel) or 16GB (dual or quad channel) of RAM. [/quote] About to purchase an iMac 27" 3.4GHz quad core... (read more)