I'm new to using Mac computers and I just purchased a new 15 inch 2.3 GHz, i7 Quad core Macbook Pro with 4 GB RAM. I write online training courses and I use two authoring tools - Articulate and Adobe Captivate. I have to run Articulate on Windows - no mac version. My question - if I understand correctly, Parallels creates a virtual system within the Mac OS X, right. Therefore, both OS's need memory, right? That is why memory needs to be allocated? How much memory should I allocate and will this impact performance when I am using Mac software on the Mac OS?