How to choose the best gaming monitor that fit your game?



For the normal user, the criteria for choosing a computer monitor is usually "resolution", "size", "color" or "sharp image" but for real Gamer, the display quality is sometimes placed after the "responsiveness" of the screen.
There are many factors that affect the final quality of the displayed image, and there are also many aspects that need to be considered. Unfortunately for us, what the manufacturer's advertisement are not always what they can archive. This article will help you understand some of the major factors that affect the "responsiveness" of a screen so you can choose the best gaming monitor that fit for your favorite games.

1. Input lag

The responsiveness of a screen can not ignore the gamer's senses when interacting with the screen, as well as the images in their eyes. Input lag is the latency that occurs between the time the graphics card starts sending a frame to the screen and when the screen actually displays that frame.
The basic characteristic of the input lag affects the user's sense of the so-called delay of the signal and is usually measured in milliseconds. Of course, there are many more factors that increase the final signal latency (weak internet connection... etc), the input lag is just one of them.

Reducing the input lag will give you a better experience, especially when playing game. The screen will process images in some way, then display them, especially a few high-end screens that will use an integrated filter for non-native resolution and this increases the input lag.
Sometimes the signal is required to go through the amplifier, although that signal does not need to be filtered (ex: using the monitor at its standard resolution). Manufacturers will sometimes give you the option to turn off these filters, allowing you to output directly to the screen (we usually see in game mode / gamer mode / game preset ... etc).
The input lag as mentioned above only contributes to signal latency, another factor that increases this latency is the time a pixel changes from one response to another. - This is a factor that greatly affects our senses when used the monitor. The response time is "visual latency" and input lag is "sensory latency".
Manufacturers are more interested in the input lag (although response time is far more important), which makes many people mistakenly prefer to choose lower screen input lag, although sometimes the monitor has a higher response time.

2. Refresh rate

The next factor affects the visual perception of the gamer is the refresh rate. Most currect LCDs have a default resolution of 60Hz, which means that each second it displays 60 frames with a 16.66 millisecond space between each frame. For higher frequencies such as 120Hz or 144Hz, the number of frames displayed per second is increased as well as the "space" between frames is significantly reduced (8.33 millisecond with 120Hz and 6.94 millisecond  with 144Hz).
Refresh rate of monitor
Look at the above picture we will see 60Hz screen only display a frame between frame 1 (red dot) and frame 2 (yellow dot). At the same time, the 120Hz screen display 2 frames, showing frame 2 (yellow dot) after the first 8.33ms, then switch to frame 3 (blue dot) at the end of the cycle 16.67ms.
This means that a 120Hz screen is capable of outputting up to 120 frames per second (fps), significantly reducing blurring and smoother motion. The double display also doubles the amount of input information into the display (such as the movement of the mouse pointer), all combined to help reduce the relative input lag, allowing us to interact more closely with the device and have "better" feeling.

3. Vsync, Nvidia G-sync and AMD FreeSync

The frequency of the screen (refresh rate) and the number of frames per second (frame rate) are closely related to each other, the higher frequency the better. But to exploit all its advantages, the number of output frames must match that frequency. Some users use V-sync to prevent the GPU to output a larger frame number than the frequency of the screen, and to ensure that the GPU will only send images to the screen when the screen is ready to reach the next refresh.
The fact that the GPU restricts the frames will result in an increase in input lag, but the "side effects" are not worth the benefits. V-sync sometimes causes the FPS to drop below the frequency. In this situation, the screen has finished displaying a frame and ready to move to the next frame, however, the GPU has not yet processed the next frame, it will decide to resend the previous frame and continue to increase the latency.
To reduce the latency, you should disable V-sync. But if the frames are not synchronized, the screen will display a frame in the middle of its refresh cycle. Usually a screen will be refreshed from top to bottom, if the above phenomenon occurs, the lower half of the screen is displaying the old frame, when the upper half has displayed to the new frame - and it is called "screen tearing".
Screen tearing
Screen tearing effect.
Nvidia has had an effective way to overcome this phenomenon by launching G-Sync.
The chip synchronizes the frame with the frequency of the screen in real time, including the frame when playing games or doing anything. Just like you have all the benefits of V-Sync without having to suffer from any of its "side effects." The chip has been built into some of the gaming monitor on the market.
AMD have also launched FreeSync, basically the same G-Sync and also integrated on a number of monitors.

4. Response time

The response time is the final factor affects the "responsiveness" of a monitor. In the above refresh rate diagram you will see the "space" between each frame. On a CRT screen the spaces will be completely black, it will just blink the frames at the beginning and end of the refresh, which will make you sometimes even see the CRT " flicker".
But the LCD screen is different, LCD uses a technology called "display and hold", meaning that a frame will be a "sample" and displayed throughout the "space", then displayed next frame. Next at the end of the refresh (and the next frame is a "sample"). LCD  screens are not capable of displaying instant frames; they are affected by response time - the time that a pixel changes from one color to another.
The time is not affected by the color (for example, from blue to red), but it is affected by the brightness and intensity of the shade. People use the gray scale (darkest shade is 0% gray = black, and brightest is 100% gray = white). A pixel that changes color from black to white is usually shifted from 25% gray to 75% gray.
Short or long shifts are based on the sensitivity of each eye to each specific color. Manufacturers often record response time is GTG (Grey to Grey), typically 2ms or 4ms. However, there is no standard for this response time, because each pixel with different colors has different response times.
99% of manufacturers will choose the shortest pixel color change time and then enter the parameter (usually GTG). Here is the difference between 4ms response time and 8ms response time on a 60Hz screen:
The difference between 4ms response time and 8ms response time on a 60Hz screen.
The screen 1 takes 8ms to turn from red to yellow, and has 8.67ms to display, while screen 2 takes 4ms to turn from red to yellow, and has 12.67ms to display, which helps reduce the ghosting display. There are some external boards that will speed up the pixel coloration (Response Time Compensation (RTC), which sometimes causes the pixels to change color too. Keep changing makes the screen more severe ghosting effects (RTC errors).
RTC errors