Refresh Rate

The number of times a display can paint its screen with a complete image, or the frequency with which a video image is refreshed, expressed as either frames per second (i.e. 60 fps) or as an equivalent frequency (i.e. 60Hz).  Faster refresh rates tend to render smoother motion sequences.

With computers, the refresh rate for each display depends on the video card used.  You can change the refresh rate in the display properties.  However, if you change the refresh rate to a setting that the display or video card cannot support, the display goes blank or the image becomes distorted.  It is recommended to consult the display and video card specifications (before changing the settings) to determine the supported refresh rates.

For computer use, an older refresh rate standard, developed by the Video Electronics Standards Association (VESA), was only 60Hz.  This refresh rate caused the display's image to flicker, causing eye fatigue and headaches in users.  A newer standard set the refresh rate to 75Hz.  It is believed that 70Hz or higher eliminates the flicker.

Refresh rates for broadcast TV vary by region.  For example, European HD systems run at 50Hz.