While the Intel driver was causing high DPC latency for me, it turned out to NOT be responsible for my audio distortion and stuttering. The culprit in my case is a bug in the Nvidia HD Audio driver that occurs when ShadowPlay is enabled. It is a regression introduced within the last 6 months. The Nvidia virtual audio device causes a conflict with other audio drivers or timing issue. See the link to the Geforce forum thread regarding the issue. Uninstalling/disabling the Nvidia HD Audio device and/or disabling ShadowPlay in Geforce Experience resolved the problem. Nvidia seems to be actively investigating this issue, but there is no fix from them yet. I'm posting here in case others have a similar issue in the future.