Yea. I'd consider using Custom Resolution Utility and creating a custom graphics mode that has a slightly lower refresh rate than the current one and the artifact should stop.
I'd check to make sure there's no dust in the pci express port or on the pins of gpu. Also the gpu could be running the display at a graphics mode that is slightly out of sync with what the monitor wants and could cause that. If you have a monitor above 60 hz then try turning it down to 60 and see if that fixes the problem. If it does you'd need to create a custom graphics mode.
Yea. I'd consider using Custom Resolution Utility and creating a custom graphics mode that has a slightly lower refresh rate than the current one and the artifact should stop.