Melody Zacharias takes us through the history of tempdb improvements:
In my previous blog and this one, there is a lot of talk of trace flags and you can see the life cycle of them. They are implemented and then sometimes become part of the product over time. For a long time, the trace flag 1118 was a common performance improvement trick known only by industry experts. Over the years as a consultant, I have often been asked by clients if they should use trace flags, and generally speaking, as long as they are documented by Microsoft they are safe to use. I would certainly not recommend using undocumented trace flags. They are not supported and therefore not recommended. So always be sure to check the trace flag list before setting trace flags. So of course, as I say that, I have to offer another one.
Read on for more details and also advice on getting the most out of tempdb.