Hard drive swap space, sometimes referred to as Virtual Memory, may work OK for some tasks, but not others. I've found it useless for rotations, since to rotate a 4000x3000 pixel image in a reasonable RAM space may take only a few seconds, but could take 15 minutes when swapped to disk. Once a person gets good at image editing, they may be able to do 10 or more edits in 15 minutes, but with disk swapping, that could stretch to several hours.