The refresh rate, expressed in Hertz (Hz) describes how many times per second a picture is refreshed on the screen. The standard refresh rate is 60 times per second, or 60 Hz. However, in scenes with rapidly moving objects, a 60 Hz refresh rate can make things look blurry or jittery, particularly on LCD HDTVs. So, to create a more solid picture, manufacturers doubled the refresh rate to 120 Hz (and in some cases up to 240 Hz).
Since there aren’t that many per-second images in original video content, TVs handle the faster refresh rates in different ways. One method is to simply insert black images between the original pictures, tricking the viewer’s eyes into seeing a less blurry, more solid picture. Another technique is to generate and insert new images — showing a state of movement in between the two adjacent pictures — to display more realistic-looking motion. However, depending on how the video-processing is done, it can make a movie or sitcom look flat, or as if it were a poorly lit, old-time soap opera.
A word of caution: beware of terms like “effective refresh rate,” which means the actual frame rate is half the stated rate (e.g., a “120 Hz effective refresh rate” is actually a 60 Hz refresh rate).
Bottom line: Don’t buy a TV with less than a 120 Hz refresh rate.