Thank you for posting. The OP is not having this problem alone. I have seen 20+ Dell users posting this issue on various boards. Dell has not provided an official solution yet.
Normally, there is an option available in the Intel Graphics Control Panel. This option is inaccesible on the XPS 13 (2015). Is there another way to access this option (e.g. some windows registry? or some other tweaking?)
Alternatively, does someone have any other suggestions?