1. Have a solution with multiple C# projects
2. Press f6 / build solution
don't do anything
3. Press f6 again to build solution, time how long this takes
4. add // (empty comment) to any .cs file so that nothing changes execution wise.
5. Press f6 again to build the solution
Did you notice any difference in the build time? I tried the test also by building just the project and not the solution, with very similar result.
Either my 2012 is seriously borked or those lines of code that contain just "//" take some serious compiling. I'm puzzled why though - since the C# should have a background compiler that has figured out before I even hit F6 that no real code changes were made.
edit: It probably is no surprise if I told that 2008 was so much faster I never even noticed this sort of thing, my compile times are about 5-10x longer on 2012 using SSD than on 2008 using only HDD. I've been thinking about upgrading the computer to "complete overkill" to "solve" this issue but I've estimated that it would STILL be slower than 2008 on the current build. For reference, the projects are mostly command line apps with some libraries and there's *no* 3rd party extensions installed.