Here's a performance "gotcha" for that specific stored procedure: http://blogs.msdn.com/b/sqlserverfaq/archive/2009/10/30/sp-columns-take-longer-in-sql-server-2005-sp3-compared-to-sql-server-2000.aspx

Basically, if the database has a table with a name containing an underscore (or another wildcard character), that stored procedure uses a much less efficient method of returning the results.