I found that on a screen with a higher resolution(I'm using 4k monitor. This problem also exists under 1080p, but it is not so serious.), the window containing the Quick component will be severely stuck when moving the window along the edge of the screen.
Moving in the center of the screen will not cause serious lag.
The confusing thing is that there is no such problem under Qt6. This problem appeared in Qt5.12 and 5.15.
This example video was recorded using an official example: MusicPlayer.
Not only this example has a problem, but all other examples that use QML, Quick components or QWebEngineView have this problem.
I am using Windows 10, GTX1070 and have updated to the latest driver.