Theoretically though, if you had enough RAM, for the sake of argument say 3 or 4 gigs, then PS wouldn't have to swap at all, it could hold its entire cache in RAM. So that was my point, RAM will always be faster and always preferably, if possible.
Photoshop always says that when you install it. I ignored it cause I was too lazy to worry about it. If you're just doing small stuff it doesn't really matter. The only time it would matter is if you're a "professional" and you use it as your job or something. You would have to be working on a HUGE project or many at a time, for it to really matter than much.
Think about it logically, even big files are never usually above 10 or so MB, unless you're making a street sign or something ridiculously big like that. Then you have the program files on top of that, but I still don't see it being a huge hog until average circumstances.
Probably the biggest hog that I notice on my computer is streaming video on the internet. Especially if its java. Live video for example, where there is no set file size and it just keeps going and it keeps piling up in memory.
