I have my Dell XPS 15 9560 connected to a monitor. About 20 minutes in a gaming session, my fps will drop from a constant 120 to 40. When I check task manager, it show that my HD Graphics have a lot higher utilization than my dedicated graphics, which only happens during the fps drops to 40. I've tried changing my preferred graphics processor to Nvidia in the control panel, but it didn't work. This is also a new issue, it has only happened to during the last two days, it was fine for the last month.