Following up on Eric's expert advice on how the application is actually programmed to work on the image, there is a subsidiary question I'm not too clear on about the role of hard drives. My understanding is that they don't affect image editing unless recourse to the scratch disk is required because of inadequate physical and virtual RAM, because the image is called-up into RAM for editing. But the hard drives do come into play for calling-up the image in the first place and then re-saving it. I find with my dual core 3 GHz Xeon 5160s that these processes are not fast. Opening an image upwards of 120 MB and resaving it takes enough time to call-up Photoshop's "Progress" bars - never a good sign of computing efficiency. For my Phase-1 files, there's time for coffee or relief therefrom So I'm hoping that an upgrade to a 4 or 8 core system (probably a Mac this time) would improve file movement to a very noticeable extent, along with other tasks.