I take it never worked so what are the makers of the card and display telling you?
Since it never worked you need to RMA the suspect part(s).
The issue I have is in any game when any object moves across the screen quickly there is a very noticable amount of what appears to be motion Blur. I wish I could post a screenshot but all screenshots I take appear to be normal, I am sure that means something but I am not sure what.
I have a 144Hz Monitor, I am sure it is set to 144hz both in windows and the Nvidia control Panel. (ROG PG278QR)
I have made sure to try the monitor with all of its various overdrive settings on and off.
The monitor and my graphics card (1080ti) are both g-sync capable, turning it on or off makes no difference.
I have tried using several different Display cables, and even an HDMI cable.
I have tried at various other refresh rates (120hz, 75hz, etc).
I have tried lightboost from blurbusters with no effect. (The UFO blur test seems fine however regardless)
I have uninstalled and re-installed Nvidia drivers.
I have reformatted my computer.
I have tried other 144hz monitors - Asus VG248
The final piece of information that confuses me is the blurry image seems to appear perfectly crisp while I am above ~100 FPS in games, but anything 75 or less it is very noticeable. I am not sure why a lower frame rate in game would result in motion blur when the monitor is supposed to be refreshing either faster than the FPS or exactly at the FPS with G-sync. To give an idea of the severity of this problem, in ARPG games like Diablo or Path of Exile, I cannot read the text on the items on the ground if I am walking by them without stopping.
I cannot even think of anything else to try to fix this problem.