It is the JetBrain software. I use IntelliJ with various language plugins. It does a lot of work in the background to provide advanced features like completion, even for dynamic languages like Python.
The problem, of course, is that the new CPUs are optimized to provide better battery life under typical usage. If you've got something running in the background that is constantly re-indexing your source code, then the CPU optimizations aren't going to help you and a smaller battery is still a smaller battery.
Also, a lot of that indexing can take advantage of multiple cores, so the jump to a quad-core proc as in the 15" helps more than the minor boost in clock speed is going to. I'm usually fine with a dual-core processor unless I'm either trying to do big compilations (especially in Scala) or using JetBrains IDEs. God help me if I'm trying to do both.
The Skylake processor consumes less power than the Broadwell that was in the previous model. This is particularly true on idle, but even when doing medium tasks it is about 25% - 35% more efficient.
The problem, of course, is that the new CPUs are optimized to provide better battery life under typical usage. If you've got something running in the background that is constantly re-indexing your source code, then the CPU optimizations aren't going to help you and a smaller battery is still a smaller battery.
Also, a lot of that indexing can take advantage of multiple cores, so the jump to a quad-core proc as in the 15" helps more than the minor boost in clock speed is going to. I'm usually fine with a dual-core processor unless I'm either trying to do big compilations (especially in Scala) or using JetBrains IDEs. God help me if I'm trying to do both.