Economically, there's no real difference between productivity rising for different reasons. However, people "working more" has nothing to do with any of them - productivity measures value produced per time worked, and so rising productivity by definition means that people produce more with the same amount of time working. From this perspective, there's no reason why a productivity rise due to computers in the 2000s should be any different from a productivity rise due to better factory equipment or production processes in the 70s.