Been having DPC issues for a very long time now, with it sometimes being blamed on ATAPORT.sys or USBPORT.sys, or sometimes nvlddmkm.sys or dxgkrnl.sys
Here is a cbs.log which says there are some issues that were unable to be fixed - maybe related?
http://www.filedropper.com/cbs1
Here is the "conclusion" from LatencyMon