How can I tell how many Cores SQL Server is actually using?

I have two servers running SQL Server.

• Server 1: SQL Server 2008 R2 Express (4 core)

• Server 2: SQL Server 2012 Developer Edition (8 core)

As far as I am aware SQL Server 2008 R2 Express should only use one core.

SQL Server 2012 Developer version should use all 8 cores.

However if I run the following command inside of SQL query on SQL Server 2008 R2 Express it's showing 4 cores.

select scheduler_id, cpu_id, status, is_online 
from sys.dm_os_schedulers 
where status = 'VISIBLE ONLINE'

Am I using the right command to gauge the usage?

Express edition is limited by 1 processor, not 1 core:


SQL Server supports the specified number of processor sockets
multiplied by the number of logical CPUs in each socket. For example,
the following is considered a single processor for purposes of this
table: A single-core, hyper-threaded processor with 2 logical CPUs per
socket. A dual-core processor with 2 logical CPUs. A quad-core
processor with 4 logical CPUs. SQL Server is licensed per processor
socket, and not per logical CPU basis.

http://msdn.microsoft.com/en-us/library/ms143760(v=sql.105).aspx

And yes, sys.dm_os_schedulers can be used to ensure, that all 4 cores are mapped with schedulers.

StackExchange Database Administrators Q#68383, answer score: 10