hello crammy90, cell-based animation is animation that is usually created by a computer. A user creates the first and last frames, and the computer generates the frames in between. Obviously this would require more processing then path-based, as the user is required to create all the frames in the animation. Path-based is also animation on a fixed background, so its obvious that path-based requires less processing then cell-based. Refer to page 227 of Heinemann textbook.
hope I helped =)