Response time is usually advertised by manufactures as the time it takes the monitor to change a pixel’s color from one shade of grey to another (GTG), or from black to white (BTW). Usually these quotes will appear on the spec sheets for gaming monitors, aimed at gamer’s who care about how quickly their monitor’s display can transition between colors as a partial measurement of the input lag.

This is not to be confused with the total input lag of a monitor, which is not advertised by manufacturers since it varies from computer to computer. Total Input lag is caused by a combination of two things – the signal processing delay caused by the monitor’s internal electronic board, and the responsiveness of the pixels (known as the response time). As explained in our “What Is Input Lag” page, you can read more about Input Lag and what goes into creating the total Input Lag of a monitor, and why it’s impossible to quote for every individual gamer. This page will be concerned with explaining the important aspects of a monitor’s response time.

Why Gamer’s Care About A Monitor’s Response Time

The response time of a monitor makes it easier to play games, especially the faster the game is (such as a FPS game). When there is a lot of fast movement on the display, it can be hard to focus if the pixels have a noticeable lag when moving from one color to another. While NO modern monitor will ever be bad in this aspect, gaming monitors can have response times of 1ms or less, making the monitors color transitions almost instant to the human eye.

Response Time on the 34UC79G
Response time illustrated on the LG 34UC79G.

The response time of a monitor becomes more important the faster the refresh rate of the panel and game is. For instance, if you are playing a game at 60FPS on a monitor that is 60Hz, the monitor and game are refreshing the screen 60 times per second. This means that 1 frame lag per second would mean you’d need a response time greater than 16.7 seconds to even notice anything. Most monitors today, especially gaming monitors, don’t have response time’s greater than this… though TV’s are a different story, however. 

At a much faster refresh rate, a 240Hz monitor showing a game at 240FPS – this would mean that any response time over just 4.17ms would show up as 1 frame lag per second at this speed. While it might not be the most noticeable thing at such a high framerate, gamer’s should care they are losing 1 frame of their game every second.

Does Response Time Cause Ghosting?

Most of the time, no. There will always be some degree of ghosting, no matter if you have a fast gaming monitor with a 1ms response time. This is contrary to what you may read elsewhere on the Internet, but please hear me out. Ghosting is the phenomenon where images appear blurry in fast scenes. You can check out your monitor’s ghosting via this popular tool. Obviously this is testing the absolute maximum of what ghosting should appear on your monitor with your current settings, but when gamers complain of the ghosting seen in gameplay, it can usually be boiled down to some other thing causing it to be much worse than it should be.

This is mostly caused by a number of things other than the response time; either the wrong cable, wrong settings used on the monitor, or the advertised response time is only with a “motion blur reduction” mode on. When you drill down into it, it usually comes out to being one of these three reasons, not so much that the monitor has a default issue with ghosting.

TN vs IPS vs VA Panels – Response Time Differences

As explained in our TN vs IPS vs VA Panels guide, there are quite some differences between the main three panel types. That being said, in recent years we have seen tremendous progress made in the display industry, so that each type of panel can have response times as low as 1ms or less.

Traditionally, TN Panels have had the lowest response times, and that still may be the case without the help of additional settings (such as Motion Blur Reduction) in order for IPS and VA to keep up.

Make sure to pay attention to a manufacturer’s quoted response time, and whether or not they used any additional settings to achieve that number.

Monitors vs TV Response Times

TV’s are known for having much slower response times than monitors, which is why professional gaming on a TV is not really a thing anymore. It used to be when TVs were CRT displays just like the monitors from that era, but now because of all the additional processing delays, even the best TV’s have a hard time getting better than a 15ms response time.

Because most TV’s are only 60 or 120Hz, a 15ms response time is decent for the average gamer. Most console-gamers tend to play on TV’s rather than monitors. But for those of us who are concerned with having the best and fastest gaming experience, TV gaming is not recommended.