They are all indications of PWM. Different cameras will show the effect in different ways and LED/CCFL look different when captured. However, you cannot rely on these videos to show the impact of PWM on the human nervous system. The second video looks very bad, but in reality the decay rate of CCFL makes it far less of an issue in real life. If you pointed the camera at a CRT running at 120hz+ you'd get a similar effect. If you pointed the camera at a CRT running at 120hz+ you'd get a similar effect. That will vary from CRT to CRT as well, depending entirely upon the type of phosphor the manufacturer chose to use. CRT monitors using "slow" phosphor will be more prone to ghosting, but will also reduce (or almost eliminate) flickering since the phosphor continues to glow for a long period of time after the gun has left the area.