What is Skylake and how does it compare with Broadwell or Haswell?

Haswell, Broadwell and Skylake are are codenames for the respective 4th, 5th and 6th Generation iterations of Intel's processor microarchitechture.

Broadwell is perceived as a version upgrade from Haswell however Sklyake is a major microarchitecture re-design.

Apple has introduced the latest lineup of Laptops that now use Intel Core M processors based on Skylake.

Core i5/i7 are faster than Core M. Core M lies in between the ATOM and the Core i5/i7 series but on a Skylake Architecture however.

Intel has the Core i5/i7 versions on both Skylake and Broadwell.