Why are not all CPU cores used?

Oopps! Upgrade your browser pretty please.Oopps! Upgrade your browser pretty please.

If you check in the Task Manager on the Server and find that it looks like this:

TaskManager

Why are not all cores used? If we make som further investigations like SQL Server properties:

Properties

SQL Server has detected all 8 cores and if we then check the Processor settings:

Processors

All cores will be used, nothing that explains the behavior.

If we than check the dmv:s we get that 4 cores is offline, what can cause that?

dmv

Finally we check the SQL Server log and in one of the startup messages you can get the solution:

SQL Server detected 8 sockets with 1 core per socket and 1 logical processors per socket 8 total logical processors; using 4 logical processors based on SQL Server licensing. This is an informational message; no user action is required

In this case we can change the vmWare setup and give the VM 2 sockets with 4 cores per sockets instead, then SQL Server can detect and use 8 cores.

/Christian