I only have experienced this in kernel 4.6.x. Downloaded from Ubuntu's ppa/mainline Ubuntu 16.04, Dell XPS15 9550, M.2 HD, 16GB RAM. After my system is suspended, or possibly just not rebooted for a while, the system becomes slow to respond. I really only use this laptop for Chrome, Firefox, a few IDEs, and Libre. I have lots of HD space and lots of unused RAM. Chrome and Firefox will become slow to open new tabs or load pages. Libre will take many minutes to save a file I'm working on. The file isn't large at all. 70k. After a reboot, the computer works great. I'm hoping you guys can help me, help you, find the root cause of this bug. IE: "Please run these commands next time this happens. Attach the output to this bug."