When we setup multiple data files for tempdb I understand SQL Server uses a Proportional Fill algorithm. How does it work? Does it use the same method for user databases aswell.
I have tried to understand it using the SQL Internals Viewer but was unable to get consistent results and hence am a bit confused.
It does use the same fill mechanism as user databases. It basically uses a proportional "round robin" format. You can read the BOL version of how it works here: http://msdn.microsoft.com/en-us/library/ms187087.aspx