How many FPS can the human eye see? That’s a tough question because the human eye doesn’t really see in “frames per second,” and everyone’s eyes are different. We’ll talk about the biology, but the real question is what the upper limit is when it comes to FPS on monitors. At what point do you stop noticing FPS increases?
In the end, for competitive gaming needs, it’s worth getting a monitor with a refresh rate higher than 60Hz—the higher, the better. You’ll begin to get diminishing returns past 144Hz, however, the only way to know for sure is to try out the monitor with the highest refresh rate that you can find!
Of course, monitors are also not just about refresh rates, so the resolution, brightness, contrast, etc also all play a role too.
See https://www.howtogeek.com/888948/how-many-fps-can-the-human-eye-see/