You can use the Lighting Build info from Statistics for a comparison and to see what meshes are taking the longest to build. If you have a scene that hasn’t changed between 4.13 and 4.14 at all that may a good indicator what is taking the longest to build and where the problem potentially lies. If you’ve upgraded your project to 4.14 and made changes I’m not sure that’s the best test case to just say that lighting is taking longer. This can help you investigate what is taking the longest to build on your machine.