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What is monitor latency (Input lag) and why it matters in gaming?

Taking a look at input lag and how it can affect gaming on your PC.

A gaming monitor

 

Monitor latency, also known as input lag, is the delay between the source of the input (keyboard, mouse, controller) and the display of the image on a monitor or a TV. In other words, it is the time it takes from when a GPU sends a signal to the monitor, for the monitor to display that frame.

The input lag is measured in milliseconds, but how quickly your frames refresh makes a huge difference in gaming, especially in multiplayer and competitive. It can be the difference between getting killed and getting a kill.

Response Time vs Input Lag

The response time and the input lag are not the same, though reading through the display manufacturer’s specs, you’d think otherwise. They are, however, interlinked.

Display manufacturers, whether they specialize in TVs, monitors or other display, do not show nor advertise the input lag. What they do advertise is the ‘response time’, but only for monitors, not TVs. Due to the way ‘response time’ sounds, it makes it appear as if it represents a ‘response’ to the input, however this isn’t the case. Response time actually refers to how quickly the pixels change on your screen from black-to-white or from grey-to-grey. In other words, it dictates how much “ghosting” appears on your screen. Ghosting is a display trail of objects or people moving across the screen. The higher the response time, the more trailing will be visible.

This is particularly evident if there is a lot of action on the screen. If there is a high response time, the pixels on screen cannot update fast enough to match the image refresh input, causing ghosting effect. In gaming, you will recognize ghosting by the blur that may appear as you, objects or NPCs move around, because pixels remain on screen longer than they’re supposed to.

When it comes to input lag and response time, the lower is always better.

What is an acceptable monitor latency?

 

An animated image demonstrating a person inputting a movement and a visible delay on screen for the game to respond

 

If you’re gaming, the lower your monitor latency, the better. The ideal is always zero, but since that’s seldom the case, here is a rough guide as to what you’d consider an acceptable monitor latency.

As previously mentioned, the input lag is measured in milliseconds.

  • 0 – 20 ms is excellent. The input from the keyboard/mouse/controller to the times the frames refresh will be instantaneous. As we previously discussed, this is extremely important to gamers, especially in competitive settings and e-sports. For a gaming environment in general, 10ms is considered ideal, and anything less than that is a bonus.
  • 21 – 40 ms is good. A good range that facilitates online gaming without hindering experience or impacting the score. The skill will come into play, but if you’re playing a game where every second counts and reaction times are important, you might get outplayed by someone with a smaller input lag, such as a pro gamer.
  • 41 – 70 ms is average. This is still within acceptable lag parameters, assuming this is the only lag that’s being experienced. A lag caused by anything else as well, such as the network, may impact your gaming experience, and you may notice the slight delay from when you click a mouse or push a button to when the action on screen occurs. It’s worth mentioning that even at 50ms, the gamers can still have an enjoyable game.
  • > 70 ms is bad. Anything above 70 ms is undesirable and would diminish the gaming experience, especially if you’re playing online with friends or competing. If you’ve ever wondered “How did I shoot first, but died”, you may want to check your set up for input lag/monitor latency. If the lag rises to 100ms and over it will make a game unplayable and if it goes into 170 ms, it will cause the game to fail altogether.

How do I reduce input lag?

 

A animated image demonstrating the latency time between moving a mouse and the corresponding action occuring

 

There are a few steps you can do to try and reduce your input lag with your current set up.

  1. If you’re playing on a TV instead of a monitor, ensure that your TV is set to “Game Mode”. This isn’t just for visual purposes; it actually has functionality. The “Game Mode” disables image processing, thus reducing the input lag.
  2. If you’re playing on a monitor instead of a TV, you can check your monitor settings for “Low Input Lag” option or a similar feature that will aid with the lag.
  3. If you’re using a controller and are having issues with input lag, consider getting a wired controller, instead of wireless. Favouring a wired controller over the wireless will lower the input lag overall. If you are using a wireless controller and are having issues with input lag, check for controller damage or battery strength. Both of these can cause input lag on top of the inherent input lag that is associated with wireless.
  4. If you’re playing on a TV screen, avoid cable adapters and splitters as both degrade the signal quality. Even the length can influence the input lag. As a rule of thumb, every 15 to 20ft, there should be a signal booster or an amplifier.
  5. Any ambient screen dimming or power saving settings should be switched off. They can increase the monitor input lag significantly.
  6. If you’re playing on TV, try using the headset instead of the TV speakers, as the TV speakers add to input lag. An alternative to the headset would be to use a separate audio system.
  7. Test your HDMI inputs and only use those with the lowest input lag. Some may have lower monitor lag than others on the same system and may be better for gaming.
  8. Consider disabling the HDMI-CEC if you’re playing on TV, as in testing it has shown to add around 10ms of input lag.

With all else being equal, trying the above solutions may decrease your monitor delay/input lag by ~30ms, which may be the difference between a game running well, a game not being able to run at all and the ability to compete online.

With the surge in popularity of online multiplayer games, many casual and upcoming gamers are starting to pay a lot more attention to the input lag. While connection, ping and state of a game’s servers are generally the main culprits for lag, those with impeccable connections can still suffer monitor latency.

Monitors are an important part of a gaming set up, and not just for visual quality. The better the games get, the more demanding the hardware to run the games will be. Monitor set up is not negligible if you’re a serious or a hardcore gamer, however even if you’re just getting into gaming, starting out with the best possible monitor, with the lowest possible latency is preferable.

If you need help choosing the best monitor for your set up, whether you’re looking to upgrade or get into gaming, check out our “How to choose the best monitor for gaming” guide.