What is disappointing is, that this feature has been shown in an early video from Dyslexi, and it seemed to work well.
The first time I have launched the Alpha, I have wondered where this features was...
What is your setting in CCC for Vsync?
On my rig, if I choose "always enabled" or "enabled unless specified by app", I get the FPS stuck to 30 or 60. If I set it to "disabled unless specifed by app", my FPS vary between 30 and 60 as intended.