The response time of liquid crystal monitors is the shortest time it takes a pixel to change brightness and measures in milliseconds.

What is computer monitor response time?

In dry scientific terms, the response time of liquid crystal monitors is the shortest time that a pixel needs to change its brightness and measures in milliseconds (ms).

Seemingly simple and straightforward, but if we look at the question in detail, it turns out that these numbers hide a few secrets.

A bit of science and history

The time of warm and tube CRT monitors with true Hertz and RGB color was already gone. At that time everything was clear – 100 Hz is good, and 120 Hz is even better. Every user knew what these numbers show – this is how many times per second the picture on the screen is refreshed, or blinked. It is better to use a frame rate of 25 Hz for TV and 30 Hz for digital video to watch a fast moving picture (e.g. movies). The basis was the medical claim that human vision perceives an image continuously if it blinks at least twenty-five times per second.

However, technology has evolved, and liquid crystals replaced CRT (electron-beam tube) panel, also called LCD, TFT, and LCD. Although the production technologies are different, but in this article we will not focus on the details, the differences between TFT and LCD will tell another time

What does the response time influence?

Therefore, the principle of the LCD is that the cells of the matrix change their brightness under the influence of the control signal, in other words – they switch. This switching speed or response time defines the maximum speed of image change on display.

In the usual hertz is translated by the formula f=1/t. Therefore, to get the necessary 25 Hz it is necessary to provide pixels with 40 msec speed and 33 msec for 30 Hz.

What is the best monitor response time?

  • If the time is long, then artifacts will appear when the scene changes rapidly – where it is already black, the matrix still shows white. Alternatively, an object that has already disappeared from the camera’s field of view displays.
  • When the human eye is shown fuzzy pictures, vision fatigue increases, headaches may appear, and fatigue may increase. This is due to the visual pathway – the brain is constantly interpolating information coming from the retina, and the eye itself is busy constantly changing focus.

It turns out that less is better. Especially if you have to spend most of your time at the computer. The older generation remembers the days when it was hard to sit in front of a CRT for eight hours a day – and they provided 60 Hz or more.

How do you find out and check the response time?

Although milliseconds are milliseconds in Africa, but probably many people face with the fact that different monitors with the same indicators form images of different quality. This situation is due to the different methods of determining the matrix response. In addition, it is hardly possible to know which measurement method was used by the manufacturer in each case.

There are three basic methods of measuring monitor response:

  • BWB, also known as BtB, is an acronym for Black to Back and Black-White-Black. Shows the time it takes for a pixel to go from black to white and back to black. It is the most honest indicator.
  • BtW – stands for “Black to White”. Turning on from inactive to one hundred percent luminosity.
  • GtG – Short for “Grey to Grey.” How long does it take a dot to change from ninety percent gray to ten percent luminance? It is usually on the order of one to two ms.

In addition, it turns out that checking the monitor’s response time by the third method will show a much better and more attractive result for the consumer than checking by the second method. Moreover, you cannot complain – they will write those 2 ms and so it will be. However, in fact on the monitor and artefacts, and the picture is dashed. Moreover, all because the true situation shows only method BWB – the first method, it indicates the time required the pixel to complete a full cycle in all possible states.

Unfortunately, the documentation available to consumers does not clarify the picture and what means by, for example, 8 ms is difficult to understand. Are it going to work comfortably In small place?

For the laboratory research is used quite a complex hardware-software complex, which not every workshop has. However, what to do if you want to check the manufacturer?

To check the monitor’s response time at home you can use the program TFT Monitor Test. Selecting the icon of the test in the menu of the program and indicating native resolution the picture of a rectangle, wandering back and forth, appears on the screen. In this case, the program will proudly show the measured time!

We used version 1.52 and checked a few displays and made a conclusion – the program shows something, even in milliseconds. In addition, the worst quality monitor showed the worst results. Nevertheless, since the time of pixel extinction and ignition is registered only by the photo sensor, which was not present in the first place, then the purely software method can be recommended for subjective comparative evaluation – what the program measures is clear only to its developers.

Much more clearly empirical test would be “White square” mode in TFT Monitor Test – a square of white color is moving along the screen, and the task of the tester is to observe a trace from this geometric figure. The longer the loop, the longer it takes the matrix to switch and the worse its properties.

That is all you can do to solve the problem of “How to check the monitor response time”. We will not describe the methods using cameras and calibration tables, but we will consider them another time – it will take another couple of days. A full-fledged check performs by a specialized organization with the appropriate technical facilities.

Response time in the monitor for games

If the main purpose of the computer – games, then it is worth picking up the monitor with the shortest response time. In fast-paced shooters, even a tenth of a second can decide the outcome of the battle. Therefore, the recommended response time for gaming monitor – no more than 8 ms. This value provides a frame rate of 125 Hz and it will be absolutely enough for any game.

At the next closest value of 16 ms in tough battles will be observed motion blur. These statements are true if the claimed time was measured by BWB, but companies can slyly write 2 ms or 1 ms. Our recommendation is unchanged: the less, the better. Therefore, for games the response time should be at least 2ms as 2ms GtG approximately corresponds to 16ms BWB.

How do I change my monitor’s response time?

Unfortunately, without changing the screen there is almost no way. It is a characteristic of the imaging layer itself and corresponds to the manufacturer’s design decision. There is of course a small loophole and engineers have solved the question: “How to change the response time”.

The companies producing monitors call it OverDrive (OD) or RTC (Response Time Compensation). This is when a higher voltage pulse applies to a pixel and it switches faster. If your monitor blinks with the words – Gaming Mode or similar, you know – there is a possibility of correction for the better. To be clear, no software or video cards changing will help you and you cannot change anything – it is a physical property of the matrix and its controller.


Buying a video card for a thousand and a half conventional units, to race your favorite game at least a hundred FPS, and give the video signal to the monitor, which and forty FPS barely pulling, a little irrational. It is better to add a hundred for the display and enjoy the full dynamics of games and movies without disappointment – you will not get any pleasure from 40 ms matrix, and the joy of owning a powerful video adapter overrides the poor image quality.

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