I need a new mac for photoshop work, working on files up to 2GB. What MAC configuration is the most cost efficient in terms of balancing price and performance, considering this is for photoshop rendering only? Will a maxed out IMAC with a separate 30" screen perform as well in real world use as a new mac pro (base model)with 64GB of ram? I am not interested in custom builds. Another question, should i get a 2012 6 or 12 core?