Just fixed this issue with a customers Vostro 3750.
The latest Support drivers cause DPC latency of half a second at a time once every 60 seconds and a lot more smaller pauses in between. The problem can be seen as mouse cursor is stuck for a moment and if there's audio, you'll hear a buzzing sound.
See more user experiences at: http://www.sevenforums.com/sound-audio/361186-audio-stutters-buzzing-caused-dpc-latency.html
A correct solution at the moment seems to be disabling the system device Dell Diag Control Device (i.e. DDDriver64Dcsa.sys) until new version is published.
Hope this helps someone to avoid all the troubleshooting we had to do...
Solved! Go to Solution.