Slava has written a great post on the information available in SQL Server DMV - sys.dm_os_sys_info. This is a great resource for finding Windows system information, such as the CPU tick count, hyperthread ratio, physical and virtual memory, as well as the worker and scheduler counts.

My favorites are -

-- How many sockets does my machine have
select cpu_count/hyperthread_ratio AS sockets
from sys.dm_os_sys_info

-- Is my machine hyper threaded?
-- Unfortunately you can’t derive this information using this DMV today

-- How many either cores or logical CPU share the same socket?
select hyperthread_ratio AS cores_or_logical_cpus_per_socket
from sys.dm_os_sys_info

You can find more information about this DMV at