Vitaly Bruk deals with a CPU issue:
Today, I investigated an interesting issue.
One of my clients called me and complained about high CPU on his server. Server with 0 load at this time frame.
Using my favorite “Activity” script and the sys.dm_os_ring_buffers DMV, I clearly saw that the CPU is being used by a non-SQL server service. Next, I’ve asked to connect SQL Server machine and opened a task manager.
Surprise, surprise! The CPU was being used by the SQL Server process! Well, kind of…
The moral of the story is to keep your systems patched.