Steve Jones - SSC Editor (8/8/2013)
Read this: http://www.sqlskills.com/blogs/paul/a-sql-server-dba-myth-a-day-1230-tempdb-should-always-have-one-data-file-per-processor-core/In general, here's what I'd say. Separate LUN if possible, but not critical. Go with # cores for <= 8. After that, stick with 8 unless you can test.
LOLZ Steve - That was the article I was thinking about when I said "I have read"....
It is also the one I pointed too when starting at my current place of work when they asked why.
Doing this has also allowed us to rebuild indexes on Standard Edition servers without taking our applications offline.
They have stopped asking why.
Paul is the go to master for SQL Deep Dive's and water ones two. 😉