Hi,
I have the same issue on my Lenovo E480. Some of it was definately to do with a BIOS update required to improve the interplay between the onboard and dedicated graphics but the problem of a sluggish windows UI remains. For me this is mostly evidenced by the fact that I get faster start menu draw from a PC I am remoted into via Chrome Remote Desktop than on the laptop itself!!
I have tried sfc, dism, set my paging size to recommended and now am attempting the edge://flags fix but I can't find the flag!
"Delay Competing Low Priority Requests" is not in the list. Am I searching wrong or is it gone?
Any other ideas?