unable to vSync on external monitor

[ilay01]

i have a dual monitor setup that consists of my laptop's screen and an external monitor.
so today for the first i tried my games on the laptop's monitor(FPS capped to the same refresh rate as the external one, 180Hz), and games seemed much smoother so ran a UFO motion test.
when i set my external monitor to "main display" in Windows Display Settings it is lagging and unable to vSync, but when i set my laptop's screen to "main display", restart my browser and run the test again it is very smooths and vSyncs almost immediately.
how can i fix this and and make the experience on my external monitor same as my laptop's screen?

[Chief Blur Buster]

i have a dual monitor setup that consists of my laptop's screen and an external monitor.
so today for the first i tried my games on the laptop's monitor(FPS capped to the same refresh rate as the external one, 180Hz), and games seemed much smoother so ran a UFO motion test.
when i set my external monitor to "main display" in Windows Display Settings it is lagging and unable to vSync, but when i set my laptop's screen to "main display", restart my browser and run the test again it is very smooths and vSyncs almost immediately.
how can i fix this and and make the experience on my external monitor same as my laptop's screen?

Windows, web browsers, and TestUFO does not support perfect Hz on anything but the Primary Monitor.

This is due to web browser limitations and operating system limitations on successful multi-Hz multimonitor. Apparently, Mac's do that much better than Windows can.

You are doing the right move, setting the external screen to the main screen -- that is the official solution.