Also referred to as “response rate” or “latency,” an LCD monitor's response time indicates how fast it can display moving images. Response time measures how quickly the monitor’s individual pixels can change colours (as indicated in milliseconds)—the lower the number, the faster the pixel change rate.
More formally defined, response time is the time it takes for an LCD pixel to change from a completely active black state, to a completely inactive white state and back again. However, in real-world use, pixels are rarely in an all-white or all-black state, so manufactures will often report the speed at which pixels change from colour to colour (also called “grey-to-grey” speed). The Video Electronics Standards Association (VESA) will soon introduce specifications to standardise response time reports, in an effort to make these numbers more comparable.
However response time is measured, faster is better when it comes to your viewing experience. If an LCD's response time is too slow, the display's pixels won't be able to keep up with the information sent from the computer's graphics card, and you'll see ghosting, streaking, and digital noise as a result. This is especially true for games, movies, and graphic applications.
While most manufacturers recommend a response time of around 12–15ms as a baseline for average use, response times are falling quickly as LCD technology becomes more advanced. For example, LG currently offers many LCD monitors with a response time of 5ms. Ultra-low response times help you get the most out of today’s cutting-edge games, videos, and graphics applications—and help you keep pace with the ever-faster applications of tomorrow.