SQL Server 2005 Ring Buffers stored information related to CPU usage. This information is updated every 1 minute. So at any given point of time you can trace back the CPU usage for 4 hours 15 minutes. A sample output below shows the SQL instance CPU utilization against the other processes (active on the server) CPU utilization. This will definitely help us identify whether the SQL Server process is actually driving CPU. 

Sample Output:

For SQL Server 2005: 

declare @ts_now bigint 

select @ts_now = cpu_ticks / convert(float, cpu_ticks_in_ms) from sys.dm_os_sys_info 

select record_id, 

dateadd(ms, -1 * (@ts_now - [timestamp]), GetDate()) as EventTime, 

SQLProcessUtilization, 

SystemIdle, 

100 - SystemIdle - SQLProcessUtilization as OtherProcessUtilization 

from ( 

select 

record.value('(./Record/@id)[1]', 'int') as record_id, 

record.value('(./Record/SchedulerMonitorEvent/SystemHealth/SystemIdle)[1]', 'int') as SystemIdle, 

record.value('(./Record/SchedulerMonitorEvent/SystemHealth/ProcessUtilization)[1]', 'int') as SQLProcessUtilization, 

timestamp 

from ( 

select timestamp, convert(xml, record) as record 

from sys.dm_os_ring_buffers 

where ring_buffer_type = N'RING_BUFFER_SCHEDULER_MONITOR' 

and record like '%<SystemHealth>%') as x 

) as y 

order by record_id desc

For SQL Server 2008: 

declare @ts_now bigint 

select @ts_now = ms_ticks from 

sys.dm_os_sys_info 

select record_id, dateadd (ms, (y.[timestamp] -@ts_now), GETDATE()) as EventTime,




SQLProcessUtilization, 

SystemIdle, 

100 - SystemIdle - SQLProcessUtilization as OtherProcessUtilization 

from ( 

select 

record.value('(./Record/@id)[1]', 'int') as record_id, 

record.value('(./Record/SchedulerMonitorEvent/SystemHealth/SystemIdle)[1]', 'int') 

as SystemIdle, 

record.value('(./Record/SchedulerMonitorEvent/SystemHealth/ProcessUtilization)[1]', 

'int') as SQLProcessUtilization, 

timestamp 

from ( 

select timestamp, convert(xml, record) as record 

from sys.dm_os_ring_buffers 

where ring_buffer_type = N'RING_BUFFER_SCHEDULER_MONITOR' 

and record like '%<SystemHealth>%') as x 

) as y 

order by record_id desc