I'm sorry that the title is confusing, but it is so complicated I couldn't make a good title. I don't know if it's in the correct stackexchange subdivision in the first place, if it's in the wrong forum, please migrate it!
HD = 1920x1080, UHD = 3840x2160
Let's say I buy a laptop with UHD screen and for example NVIDIA GeForce 980M card. Some games may run slow because the screen is very big.
Now I change the graphics settings for a lower resolution from UHD to like HD. Will changing from an UHD to HD in the graphics settings make the laptop's performance equally fast to the performance of another laptop that is physically build with HD screen, or will it still run a bit slower?