High Single Core CPU Utilization

Hi,

   We have a single instance SQL Server 2008 R2 database on Windows 2008 R2, on a dedicated database server. We are noticing that one of the CPU cores is consistently having high utilization(almost always close to 100%), even if the other CPU cores are idle(5 to 9% utilization).

The details of the configuration is as follows:

Server                        : Dell PowerEdge R810

Processor                     : Intel Nehalem 7560 @ 2.27GHz (8 core processor)

Operating System          : Windows 2008 R2(64 bit)

Database                     : SQL Server 2008 R2(64 bit)

Memory                       : 32GB

Processor Affinity          : Auto

I/O Affinity                  : Auto

Why is only the single core getting overloaded, while other cores are capable of handling load ?

One another observation is that most of the cpu is consumed by the system idle process. sqlserver process is consuming < 10% of the total cpu utilization.

Any help in understanding the issue is highly appreciated.

Thanks and Regards,

Jisha