The end of Dennard or frequency scaling in computer processors nearly twenty years ago has caused a transformation in computing. Innovations in computer architecture have enabled continued improvements in performance, but at the cost of increasing software and algorithmic complexity. Software has also undergone major transformations, making it both easier and harder to exploit the changes in hardware. This talk will provide some background on the transformations in computing over the last two decades, how the National Center for Supercomputing Applications has adapted to these changes, and how performance engineering can help guide the developments of algorithms and applications in this rapidly changing environment.