Look, how many bits you choose to process in the privacy of your own home is entirely your business, but don't expect the latest Photoshop to work on anything less than a 64-bit multi-core Mac running a minimum of Snow Leopard. Adobe's update brings a compute-heavy 'Mercury Graphics Engine' as well as better 3D and video manipulation, with the sacrifice of 32-bit support unless you're running Windows -- although even then certain features will be limited. The message is clear: jump on the upgrade treadmill or sacrifice 65 user-feedback-inspired features and a new crop too
