In general terms, timephased means that the cube allows you to see data by time. A non-timephased cube does not. In other words, the assignment non-timephased won’t give you the ability to see assignments for the month of May, but it will allow you to see all assignments for a particular project or resource. The non-timephased version is a much smaller cube and more performant than the equivalent timephased version, so if you don’t need show or filter by time on your report than you should use non-timephased. Hope that helps.