A television’s input lag is the amount of time that elapses between a picture being generated by a source and that image appearing onscreen. When gaming, you’ll experience this as the time between making an input and seeing the reaction appear onscreen. It’s only important for gamers, and even then, different gamers will have different sensitivity to lag.
We record the lowest input lag time of which a TV is capable, the amount of lag present when motion interpolation is enabled, and the amount of lag a TV has when using our calibrated settings at different resolutions and refresh rates.
Update 09/21/2017: We have changed our testing methodology to use a new input lag tool. As a result, we have now measured 1080p @ 120Hz input lag for all supported TVs we have in our lab.
Update 09/14/2016: We are now testing input lag in various resolutions, including 4k and HDR. We've retested all 2016 4k TVs that we bought so far. For testing 4k and HDR, we are using the Leo Bodnar tool chained into the HDFury Integral and the HDFury Linker to upscale to 4k and inject HDR metadata. These tools don't add any significant input lag to the measurements.
Note: Input lag is not the same as response time. The response time is the time it takes a pixel to shift from one color to another, which is significantly shorter than the input lag time. Response time is related to motion blur.
For older models, see our results for 2013 and 2014 TVs.
When it matters
Input lag only matters for playing video games, either on a console or on a PC.
With fast-paced games like shooters and fighting games, quick reflexes are key. Lower input lag can mean the difference between a well-timed reaction and a move that takes too long to register and ends up countered by the opponent before it can ever be performed. This lag doesn’t matter for watching movies, though, so unless you’re a gamer and are worried about PC peripheral lag, or Nintendo, Xbox One, or PS4 controller input lag (or other controllers too), you have nothing to worry about. Most people will not notice under 50 ms of input lag while more competitive gamers should look for a TV that can do below 40 ms. Almost everyone will also find anything over 100 ms terrible to play with.
4k @ 60Hz Input Lag
This input lag test represents the lowest lag a TV is capable of achieving with a 4k @ 60Hz signal. This is the amount of lag that is best for gamers on newer consoles such as the PS4 Pro and Xbox One X or PCs, and is pretty important for most fast-paced, competitive games.
We use a custom tool to perform this test, as it provides an accurate, continuous measurement of a TV’s input lag. To get the lowest amount of lag on most TVs, it’s necessary to enable game mode. On some, though, special steps are required, which we always list in the settings page of each TV.
1080p @ 60Hz Input lag
This test is similar to the 4k @ 60Hz Input lag test, however a lower resolution 1080p @ 60Hz signal is sent to the TV instead. This number is important for most gamers on console or PC which have a Full-HD or 1080p output, such as the PS4 and Xbox One. It is the lowest input lag the TV is capable of acheiving, ususally in a 'Game' mode. We use the same custom tool as the 4k @ 60Hz input lag for this test.
4k @ 60Hz + HDR Input lag
This test is similar to the 4k @ 60Hz Input lag test, however an HDFury Linker is chained between the PC (pattern generator) and TV. This allows us to send an HDR signal and measure the input lag with the same custom tool as other input lag tests. A low 4k @ 60Hz + HDR input lag number is important for people playing HDR games on new consoles (Xbox One X or PS4 Pro) or with a PC.
1080p @ 60Hz + HDR Input lag
Similar to the 4k @ 60Hz + HDR Input lag test, however a 1080p @ 60Hz signal is sent to the TV before the HDFury Linker injects HDR metadata. This is important for PC gamers who plan to use HDR at a full-HD resolution and is usually lowest in 'game' mode.
4k @ 60Hz Outside Game Mode
Our 4k @ 60Hz Outside Game Mode measurement represents the amount of input lag that is present when a TV uses our posted review settings – no game mode, no motion interpolation. Game mode disables many of the picture options a TV has, so this test is useful for people who want to play games with all of the TV’s settings available to them.
We use the same testing process as for the first test, only we don’t enable any settings other than what is used by our test calibration and send a 4k @ 60Hz signal.
1080p @ 60Hz Outside Game Mode
The 1080p @ 60Hz outside game mode measurement is similar to the other 'Outside Game Mode' test, but with a 1080p @ 60Hz signal. It is useful for those who want to game with the most accurate image or with processing options available. The method is the same as the other input lag tests, however the TV is left at calibration settings.
4k @ 60Hz @ 4:4:4 Input Lag
This input lag test represents the lowest lag a TV is capable of achieving when displaying a 4k @ 60Hz @ 4:4:4 signal. You can read more about 4:4:4 here, however it is generally only useful for PC use. For most TVs this requires changing to a PC mode or input icon, however you can see our settings page of any TV for more information.
For this test we use the same method as other input lag tests, however we additionally test that chroma subsampling is displayed correctly.
1080p @ 60Hz @ 4:4:4 Input Lag
Similar to the 4k @ 60Hz @ 4:4:4 input lag test, however a 1080p signal is sent. For most TVs this requires changing to a PC mode or input icon, however you can see our settings page of any TV for more information or see down below for a general guide. The test methodology is the same as other input lag tests.
4k @ 60Hz @ 4:4:4 + 8 bit HDR Input Lag
This test is performed in the same way as the other HDR input lag tests, however a 4k @ 60Hz @ 4:4:4 8 bit signal is sent to the TV. It is useful for those who game in HDR on PC and want to ensure text is clear across all backgrounds. For most TVs this requires changing to a PC mode or input icon. Slightly more banding may be visible than 10 bit HDR, however the bit depth is limited by the HDMI 2.0a standard.
1080p @ 60Hz @ 4:4:4 + HDR
This test is similar to the 1080p @ 60Hz + HDR test, however a full chroma (4:4:4) signal is sent to the TV. This is useful for those who game on PC in Full HDR with HDR and want to ensure text is clear across all backgrounds.
4k With Interpolation
This input lag time represents the lowest amount of lag a TV can get with the motion interpolation feature (soap opera effect) turned on and a 4k signal. If you want to increase the frame rate of videos by adjusting the TV’s settings, this is a test you should care about. Just keep in mind that this setting will usually have significantly higher input lag than the TV’s minimum, and so isn’t great for competitive games (it works well for most RPGs and turn-based games, though).
We use the same testing process as for the first test, only instead of enabling game mode, we enable motion interpolation at its highest setting.
On most TVs, this isn't playable for fast games. Some people chose to live with the higher input lag in order to get the smoother motion. Learn more about motion interpolation.
1080p With Interpolation
Similar to the 4k with interpolation test, however a 1080p signal is used. This is useful for those who enjoy smoother motion by adding the soap opera effect. It generally increases the input lag significantly and may not be playable for fast-paced games.
1080p @ 120Hz
This is similar to the 1080p @ 60Hz input lag test, however a 120Hz signal is sent to the TV. It is useful for thise who enjoy gaming at high refresh rates on a PC.
How input lag is measured
Input lag is not an official television specification because it depends on two varying factors: the type of source and the settings of the television. The easiest way you can measure it is by connecting a computer to the TV and displaying the same timer on both screens. You can find a timer here. Then, if you take a picture of both screens, the time difference will be your input lag. This is, however, an approximation, because your computer does not necessarily output both signals at the same time. In this example image, an input lag of 40ms (1:06:260 – 1:06:220) is indicated.
In our tests, we measure input lag using a dedicated device made just for this purpose: our input lag tool. This is a lot more accurate than the two screens method.
Why there is input lag on TVs
There are three main functions that delay the television: acquiring the source image, processing the image, and displaying it.
Acquisition of the image
The more time it takes for the TV to receive the source image, the more input lag there will be. With modern digital TVs, using an HDMI cable will allow you to minimize the acquisition time, as that will transfer from the source a digital signal that is easily accepted by the TV.
You might find a bit more lag is present with analog connections, like component or composite cables. This is because the TV needs to convert the analog signal to digital before video can be displayed, and the conversion process takes time.
Once the image is in a format understandable by the video processor, it will apply at least some processing to alter the image in some way. A few examples:
- Adding overlays (like menus)
- Adjusting the colors and brightness
- Interpolating the picture to match the television's refresh rate
- Scaling it (like 720p to 1080p, or 1080p to UHD)
The time this step takes is affected by the speed of the video processor and the amount of processing needed. Though you cannot control the speed of the processor, you can exercise some control over how many operations it needs to do by enabling and disabling settings. The more settings you enable, the more work the processor needs to achieve.
Some televisions have a dual core processor in them. This can help reducing the input lag if a lot of processing options are turned on.
Displaying the image
Once the television has processed the image, it is ready to be displayed on the screen. This is the step where the video processor sends the image to the screen. The screen cannot change its state instantly, and the amount of time it will take depends on the technology and components of the television. There’s unfortunately no way to improve or control the amount of time taken by this phase; it is a fixed amount of time for each television.
How to get the best results
Most televisions can be adjusted so that they do not have high input lag. As a general rule, try the following (which is how we set up the TVs in our tests):
- Set the TV to Game or PC Mode
- Disable all of the television's settings
Additionally, you can try different combinations of settings/modes/inputs until you arrive at whatever balance of features and input lag that you like.
Here are the steps necessary for getting minimal input lag on TVs from several brands:
- Samsung: Go to Menu > System > General and set ‘Game mode’ to ‘On.’
- Sony: Go to Menu > Picture adjustments and set ‘Picture mode’ to ‘Game.’
- Vizio: Go to Menu > Picture > More picture and set ‘Game Low Latency’ to ‘On.’
- LG: Go to Menu > Picture and set ‘Picture mode’ to ‘Game.’
- Game mode will disable some of the television's most time-consuming processing. However, gaming mode is not necessarily the setting that guarantees the lowest input lag of the television; you will sometimes need to play with the other settings to get the optimal input lag time.
- Inside game mode, it doesn't really matter what settings you turn on.
- The input lag varies slightly depending on the input resolution and frame rate.
- The input lag also varies in time. On some TVs, it even varies +/- 5ms.
Input lag is the amount of time that elapses between performing an action with a source device and seeing the result onscreen. It’s important for gaming, and is particularly important for fast-paced, competitive games. Anything below 50 ms is unnoticeable by most people. We test to find the lowest amount of lag a TV can have, as well as how much lag is present when a TV has motion interpolation enabled, or when it has normal, non-gaming picture settings on.
To improve the amount of lag, the best thing to do is use ‘Game’ or ‘PC’ mode on your TV (depending on the brand). If you want to use other settings that aren’t available in game mode, you’ll unfortunately need to deal with a higher amount of lag.