Hello to all. Before the holidays I started having a problem that suddenly appeared to me on my pc; that is, it started to give stuttering problems on benchmarks and games (lighter) that I have never had before.
I did several tests:

Formatted and installed clean windows 10 1909

Tried another gpu strix rtx 2080ti

Try dozens of drivers

Ram tested bench by bench

Nothing .... the problem remained

This morning I discover the bitter truth and the culprit.
My Asus Swift 25 "240hz monitor!
By deactivating the gsync the stuttering disappears !!!
I do not understand .... yet I have always used gsync in games and benchmarks in the past and I have never had problems.
I also tried a second monitor (which however is 60hz and without gsync) and not a problem, but I would not want stuttering at such a low frequency not to be noticed.

At this point is my monitor gsync not working properly anymore? What can I do?
After a lot of hours trying and trying I'm exhausted and I don't even know where to bang my head ... the boxes turn around a bit and I can't use gsync anymore.
Can I have any opinion or advice? Thank you all.