high cpu utilization on one cpu in an SMP configuration

Hi,

We have a file server running 2008 R2 SP1 with 8 CPUs (4x2 cores) with vmxnet3 network adapter.

We are troubleshooting high cpu utilization on one cpu.

We're speculating that DPC paritioning is the cause of this, as the file server has high network connections (not necessarily traffic) based on this MS article

http://technet.microsoft.com/en-us/library/cc938644.aspx.

We are hitting over 50% for % DPC Time.  The problem is that the first cpu can hit 100%.  Is there some tweaking we can do on the vmxnet3 network adapter to improve performance other than adding another network adapter as the article recommends?

Based on your experience, aret there other reasons why this can be happening?  We haven't changed Processor Affinity on any process.

Thanks,

rudif1