I didn't put the frame counter(even because i'm convinced it makes games run worse) so i don't know exactly, sometimes there's a frame dip during exploration when activate detective vision, but other than that it runs very fluid most of the times even with the cars minigame that's probably the heaviest minigame.
The intro movie runs slower than its music though, i had the same problem with another game and i resolved it but i don't remember how now.
EDIT:
from the GPD Win thread
For those of you that are interested:
Danganronpa 3 Demo ver: Runs between 24 -50 frames from what I can tell there's no customizable options from what I can tell
there are (very few and basic)options though, when i started the settings tool the resolution was set at 1080p, i wonder if he changed it.