Blur Busters Forums

If the game limiter isn't accurate and fps deviate from what you set or you don't cap fps, when they approach Hz (144 in this case) the tear line will appear.
That's probably why sometimes you see it and sometimes you don't.
With an accurate limiter you can see this behavior clearly.

Let's say it's 143.92 Hz.
If fps are set accurately to 143.00 the line will move down slowly.
If fps are 144.00 the line will move up slowly.

It doesn't make sense. I did not see anything like it 20 years on x monitors and now I Am seeing it! It will be something else IMHO. Now I did not see it awhile...

From what you describe it is not something else.
Horizontal colorless line splitting image in two is a tear line caused by what I already explained.
I'll just let Chief explain it if this catches his attention.

Again I said I believe you. But I don't know why I didn't see this ever, until now, each time fps goes close to refresh rate. I used to cap fps also in certain games close to refresh rate. It is weird, it is so apparent if you look at it and even from peripheral vision you can notice it sometimes...