I have a Mac Pro with the standard 1 gb of ram and I'm getting a lot of spinning beachballs and lock ups. I would love to put 4 gb of ram in but the budget right now only allows for 2 gb of ram. What I was wondering is if that will give me a much better bang for the buck than what I have now. Also., is there an dramatic difference between 3 and 5 gb of ram? Where is the "sweet spot" with ram on this machine? BTW, i use it mostly for word processsing, Itunes, test construction and the like. No heavy processor intensive applications. Appreciate any and all advice.