sql server usage

SQL Server 2005 Memory Usage?
SQL Server memory usage is more than twice the total size of all the tables and indexes in the database in a heavily queried moderate sized database. Any thoughts?
Thanks for the help so far.
The database and log file combined size is less than 1/3 of the memory being used. The clustered index on the main table seems to be using 80% of the buffer pool. The amount of data and the number of tranasction really don't suggest such a large memory usage.
The problem also continues even after a restart.
Caching. Your system is caching queries as to help speed response times, but this may produce inaccurate or out of date data if dealing with real time information.....this is not such a bad thing in a data mining situation.
You should check your settings and the cache size in memory.
[phpbay]sql server usage, 30, "11211"[/phpbay]
[phpzon]sql server usage, 5, Electronics[/phpzon]
JOINs and UNIONs - How Do I Know When to Use a JOIN or UNION