SQL Server 7.0 allows the tempdb system database to expand automatically as needed, rather than failing with an out-of-space error. If a reporting application needs a lot of space in tempdb, SQL Server 7.0 lets tempdb to grow automatically to the size needed. SQL Server 7.0 reinitializes tempdb to the previously configured size the next time the server is started.
However, remember that if the tempdb database expands too frequently, performance can be affected. One option is to set the original size of the tempdb database files to a reasonable size to avoid the files from expanding automatically as more space is needed. Also remember to set the file growth increment percentage to a reasonable size to avoid a file growth that’s too small compared to amount of data being written. Thus, you can avoid its need to constantly expand.