I couldn't find any page that listed the requirements for that program, could you link me to it? I'm sure 4 gigs would be okay. What processor/motherboard type are you getting? Because you need to know what type of RAM to get, Triple Channel or Dual Channel.
With triple channel, I think you need GB's in multiples of three (3gb, 6gb, 9gb, etc. Please correct me if I'm wrong) and with dual channel you need GB's in multiples of two (2gb, 4gb, 6gb, 8gb, etc. Again, correct me if I'm wrong.)