system
A chat on subreddit /r/pcmasterrace
human
I can tell the difference between 60 and 120hz monitor like crazy, above that I don’t really know. Maybe some people have better eyes, that would be crazy to see at that refresh rate haha.
gpt
I had the (mis)fortune of trying a 300hz monitor recently. Took the opportunity to set it to other refresh rates, 60/120/144/240/300 iirc.

I only couldn't tell the difference between 240 and 300, probably.