Specifically, I have an Acer PG278QR monitor and I noticed that I was getting major stuttering (according to testufo's animation graph) at 165Hz, while much less at 144Hz, and none at 120. I viewed the resolutions through CRU and noticed that 24 - 120Hz resolutions were (+ / - ) and 144 - 165Hz were set to ( + / + ):
So what role does sync polarity play for resolution and can it cause stutter?