It is better to try both(temp tables and table variable) before deciding. A stored procedure I am working on requires two temporary structures. However, one of them needs rows to be inserted using a dynamic query and since table variables cant be used in a dynamic query ( uncless offcourse you create the table variable itself as a part of the dynamic query) I chose to use temporary table for that one while I used table variable for the other. But i did test both separately and inspite of the large number of rows, table variable gave me a lower processing time ( for about 5 million rows)