So I'm set to buy a new mac pro and I need to decide between the base 2.8 octo core or quad core. I will be using it mostly for heavy audio editing in logic pro (recording full bands). I'm tempted to plunk down the extra $500 on the 8 core, but I also feel I might be better served putting that money towards more ram. So my question is: how much of a difference will I see, either now or in the future, between the two models? Keep in mind I plan on having this thing for the next 4-5 years.