So I had this problem after I upgraded my computer to a 8700k and kept my GTX970.
I recently got a 144hz monitor as well ..
Turns out it was the screen's problem, I have a 60Hz monitor as secondary monitor running on a DVI connector.
And Nvidia+Windows 10 has some problem with that..
Reddit with more info:
https://www.reddit.com/r/pcmasterrac..._monitor_with/
Basically you can move the secondary monitor to the internal GPU (mobo) or put main screen (144hz monitor) to 120Hz (double 60Hz which evens out the problem)
Using only displayport cables might also work..
No idea if this is the problem everyone else is facing but I'd put it here just in case.