As Fast As Possible
Response time is a measure of how quickly a pixel can display a change from either black to white or from one shade of gray to another. Lower response times are better. Normal response time right now is 1ms for TN panels and 4ms for IPS and VA panels.
A term that is often misunderstood by people is a monitor’s response time speed. It is not the same as input lag – which is a specification that display manufacturers do not advertise. Input lag is the delay between a keystroke or mouse click and the result happening on the screen.
The monitor response time, on the other hand, is specified by the display manufacturers but only for monitors, not for TVs. You might hear all about screen size, resolution, color reproduction, and refresh rate but response time is discussed less among people.
How Important Is A Monitor’s Response Time?
Response time can make a huge visual difference when there’s a lot of action happening on the screen. This spec is less about how your monitor will eventually display inputs from your peripherals after a delay and more about the individual pixels themselves.
It is a measure of how quickly a pixel can display a change from black to white or from one shade of gray to another. Different shades of gray represent how intense any given color will appear on your monitor through a filter.
The darker the gray, the less light will pass through the said color filter and hit your eyes, which is exactly why you don’t hear people talking about blue to red response times or things like that.
Response times are often given in milliseconds since one frame on a standard 60Hz monitor stays on your screen for just under seventeen milliseconds. The pixels themselves need to transition more quickly than that so that they can display the next frame in time. But just because a monitor has a response time below 17 milliseconds, it doesn’t mean that it is just as good as anything else.
A longer response time often results in a phenomenon called “ghosting”. This is when you can see the remains of trails from a moving object on a screen because pixels took too long to switch between shades of gray. This is really not a huge deal if you just use your computer for everyday browsing and social networking, but if you are a gamer or like to watch movies with fast action, then poor response times can cause really distracting visual artifacts.
TN vs IPS vs VA: Response Time
There are three different panel technologies you will meet when looking for a monitor.
First off, the TN (Twisted Nematic) panel monitors feature the fastest response time speed of only 1ms. However, they also provide very narrow viewing angles which cause the image to shift in color and contrast when it’s viewed from below or from the sides. Moreover, they have the worst color reproduction out of the three panels.
The TN panel monitors are therefore mainly used by professional and competitive gamers, and paired with a higher 144Hz refresh rate for the smoothest fast-paced gameplay experience.
IPS vs VA
Moving on, there are IPS (In-Plane Switching) and VA (Vertical Alignment) panels which are more alike. Both of these panels will provide you with wide 178-degree viewing angles, although with a VA panel you may still encounter some slight shifts in contrast, though it’s not as critical.
While the IPS panels have more accurate and consistent colors, the VA offers a higher static contrast ratio. This makes the IPS monitors ideal for color-critical work while those who want truly black colors and the brightest whites should go for a VA panel display.
So, how does the response time compare between these two?
Well, both VA and IPS newer monitors will have either a 4ms or 5ms response time specified, but due to the darker image of the VA panels, pixels actually take longer to change back from such deep black shades which results in more visible ghosting or trailing.
In the end, most people wouldn’t even notice the difference between 1ms and 4ms, so you should get either an IPS or a VA panel display depending on your preference. But if you mostly play fast and competitive FPS games, stay clear of the VA panels.
We’ve left out OLED displays which have the fastest response time speed (less than 0.1ms) but for now, there are no OLED monitors except a few very expensive ones aimed at the high-end professional designers.
In the past, monitors did have noticeably slower response times. Nowadays, if you need a monitor for everyday use, casual gaming, and such, you should avoid getting a TN panel display because you can get an IPS or VA monitor at basically the same price but with much more vibrant colors and wider viewing angles.
If you’re a hardcore FPS gamer, go with the 1ms response time speed of the TN panel and enjoy the ghosting-free gameplay.
Rob is a software engineer with a Bachelor’s degree from the University of Denver. He now works full-time on writing for DisplayNinja while coding his own projects on the side.