Moving one TempdB on 3 instance server I have a large virtual SQL Server (Full 2008R2).

I run 3 SQL Server instances and would like to relocate the TempdB database file to another location, splitting off from the TempdB log file.

The trouble I am having is that, even though the query ALTER DATABASE executes successfully, and then restarting that particular instance's SQL Server Service, does not relocate that database file. 

Do I have to restart the whole server to move this database?
Tempdb files are recreated each time the sql server starts.  After you change their location using ALTER DATABASE, you can verify your change by checking the dmv tempdb.sys.database_files.  (not sys.master_files, which won't be updated until sql restarts).  

Sql will create new files for tempdb, and will leave the old ones on disk, so you should delete them.