I use iphone to take video then download the *.MOV files to Windows 10 and edit in MS photo 

The videos play smoothly however when I edit the videos (Edit & Create -> Create a video with text), it becomes very choppy.  It used to work fine.

I tried updating video driver, repair/ reset windows photo app but still experiencing the same choppy editing problem.

How I can solve this problem?

All I want is simple video editing, speed, add the background music, text etc.

Thanks.