After upgrading to SQL 2005 from SQL 2000, SQL process using very little RAM?

[Amit]

We have recently upgraded from SQL Server 2000 Enterprise Edition to SQL Server 2005 Enterprise Edition. The total RAM available on the server is 8 GB and we have modified "Maximum server memory (in MB)" to 7000. At present the SQL Server is running fast and there are no issues affecting users. However I have noticed that the sqlservr.exe process is only using about 145MB when checked from Task Manager. In our SQL 2000 environment, it uses to use almost 6 GB. The size of the database is around 4 GB and it has lot many stored procedures which are run very frequently by thousands of users every day. There have been a couple thousand users logged on as of now and running large reports however the RAM usage is very less which is very surprising. Are there any memory issues??

[Admin]

You shouldn’t use Task Manager to check the memory usage when using SQL Server 2005 and higher versions. To check the SQL Server Memory usage start using performance counter which are mentioned below.

SQLServer:Memory Manager: Total Server Memory (KB) :- It informs you how much memory is currently being using on the server. This includes the total buffers which are committed to SQL Server Buffer Pool and Operating System Buffer Pool.
SQLServer:Memory Manager: Target Server Memory (KB) :-  It informs you how much memory SQL server would like to have in order to run properly.
SQL Server: Buffer Manager: Buffer Cache Hit Ratio: - It should have a value greater than 99%.
SQL Server: Buffer Manager Page Life expectance: - It should be always be greater than 300 sec
SQL Plan Cache Size + SQL Buffer Cache Size = SQL Total server memory.

If SQL Server requires more memory to execute then the transaction will put the load on your I/O thereby increasing the physical queue length. One more improvement in SQL Server 2005 is that it will not take all the memory it has at the start up. It consumes the memory as and when it is required; where as in earlier versions of SQL Server it used to consume all the available memory at the startup.