The last few years have been mostly about performance per watt. I changed my notebook a couple of years ago, jumped from an i3 3200 to an i5 7200U. I got 80% better performance (on numerical code) at 15W, instead of 35W for the i3. Unfortunately manufacturers cheaped out on the battery, so I went from 6 cell to 3 cell, for about-ish the same battery life I had on my previous notebook.