I'm a graphic designer. Been designing high-end sites and print collateral for years now. I'm clueless on hardware and what 64-Bit means. I've read some stuff. Will someone please kindly explain to me what that means? How much of a speed improvement will I see in Photoshop CS5 vs CS4? I'm on the last generation MBP, 2.66, with 8 GB of RAM. Thanks!