I think many laptops CPUs and video chips are too slow to run games on a 4K and HD HDMI external monitor when the screen resolution is set to 4K and other higher resolutions like 2K, 1080P, and sometimes 720P in games video resolution settings.
Sometimes laptops are too slow to play games on the laptops' 1080P or lower resulotion built-in display.
If you are using both your laptop, and an external monitor for dual-screen gaming, your laptop's CPU and video chip may not be able to handle the extra screen, so it runs games slower when there are two screens being used on a laptop.
Sometimes laptops are too slow to play games on the laptops' 1080P or lower resulotion built-in display.
If you are using both your laptop, and an external monitor for dual-screen gaming, your laptop's CPU and video chip may not be able to handle the extra screen, so it runs games slower when there are two screens being used on a laptop.