Schypder stated...
Here's an experiment. Have a low-power strobe (so you don't wind up with much afterimage burnin on your retinas) flash on a rotating wheel of white and black stripes in a dark room. It should look like it's rotating at a slower speed, or backwards, or whatnot. Turn up the speed of the strobe until the wheel looks like it would under normal light (that is, blurred to a gray). Whatever rate the strobe is running at just before that happens is technically the highest framerate your eyes can distinguish. Of course, this doesn't take into account phosphor decay rates and other such phenomena, but it should be pretty close. And note that it will vary - although probably within an order of magnitude - for different people.
XaiaX mentioned...
There was some sort of test.
There was an LED that blinked at whatever Hz. They set it to 30, and when it was still, it looked like a solid light.
They started moving the light, most people could distinguish up to around 3000 fps.