When you say found, was that experimentation or calculation? ToTTenTranz was suggesting the ideal framerate was determined logically rather than experiementation, which I don't believe. I'd also argue that the idealframerate depends on content being shown including speed. A camera filming a fast pan at 72 Hz may look smooth due to natural motion blur, whereas a computer game could look a bit juddery. If working with perfect frames and no motion blur, the required framerate to appear smooth will need to be faster. I've never done any experiements trying different refresh rates or the like, so I have no personal insights to contribute.