2007 and 2010 Cube

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.