I work with big pictures of 700 MB, and I work with aprox 3 pictures at a time.
Work on a Mac Pro 10.6.8. 9 gigs Ram. My photoshop is normal at the beginning but sows down until it is unbearable. What is the problem?
Well, you should do the normal maintenance stuff: trash the prefs, shut off anything else running, in preferences, how much RAM is allocated to photoshop? How about undo levels? for each 700mb image, how much does it say is being used in RAM in the lower-left corner with the file open (example: I have a 1.7mb JPG, letter size, 300dpi, but it registers at 24.1mb when open)? The difference is photoshop keeps the entire image in memory - not just what you see on screen and it can vary depending on a whole host of factors. May have to do one pic at a time?