Dell has not yet eliminated the DPC latency issues that have been affecting the XPS 15 9570, but it has promised that they will not be present on its successor, the XPS 15 7590.
https://www.notebookcheck.net/Dell-confirms-that-the-next-XPS-15-will-not-have-the-DPC-latency-issues-of-the-XPS-15-9570.423048.0.html