Both competitive and casual gamers need to have lightning-fast reactions, and any hesitation can make the difference between winning and losing. The last thing any gamer needs is their equipment being slow to react to their actions. There are many different components in a typical PC gaming setup, and each piece introduces its own latency or input lag, causing a small delay between when an action is registered and when it actually happens on-screen. The key to victory is having the least amount of latency possible, and although most people can't visually tell when there's latency, it can make a huge difference in games.
We already measure the input lag of monitors, which is the last piece of equipment that introduces lag. Your actions are first registered with either your keyboard or your mouse, and we've already been able to measure the latency of mice, so now we're focusing on keyboard latency. We test for it using a 360Hz monitor and a high frame rate camera.
Keyboard latency is extremely important for gamers, and although most have good enough latency for office work or programmers, a gaming keyboard with high latency can be the difference between a win and a loss. The keyboard, along with the computer and monitor, each contribute to latency between your input and the action being completed, so you want to make sure each piece doesn't have a ton of latency. Although no equipment is completely free of lag, gaming keyboards are designed to have the lowest latency possible.
There are a few factors that contribute to the latency. The type of connection used is a major factor, as wired connections tend to have the lowest latency, while Bluetooth connections tend to have the highest, which is why Bluetooth keyboards are good for typing, but not for gaming. Once your keyboard registers an input and sends a signal to your computer, your PC processes the information and displays it on the monitor, and all these steps take some time to complete, even if it's a few milliseconds. The key for gamers is simply to have the least amount of latency possible, and that starts with the keyboard.
The way we measure the click latency is fairly straightforward, but at the same time, it can be a long process to do. We use a few different pieces of equipment, including a Sony RX0 II camera, a computer with an NVIDIA RTX 3080 graphics card, a Dell Alienware AW2521H monitor, a SteelSeries Rival 3 mouse, and a solenoid connected to an Arduino Uno, which is used as a plunger, as part of the setup.
Through the GeForce Experience software, we have access to the NVIDIA Reflex Latency Analyzer program. This program is only available with compatible 360Hz monitors, which is why we need to use the AW2521H. It measures the latency between a mouse and a monitor, but it only works for mice, so we can't use it to measure the click latency on the keyboard. To measure the PC and display latency (or system latency), we enter the 'Shooting Range' in Valorant with the gun pointed towards a dark corner so we can clearly see when the muzzle fires. We make sure the Ultra Low Latency Mode is enabled in the NVIDIA Control Panel and we enable Game Mode in Windows to ensure we're getting the lowest input lag possible. We then measure the system latency by firing the in-game gun 21 times, and we use an average of the last 20 measurements to calculate the system latency.
We repeat the same process with the keyboard, but since the NVIDIA Reflex Latency Analyzer can't measure the click latency of the keyboard, we need to use a camera. If the keyboard has multiple debounce time and polling rate settings available, we use the lowest debounce and highest polling rate settings. In simple terms, debouncing is when the keyboard introduces a slight delay after a switch is actuated so it knows for sure that switch was pressed. Polling rate is how many times every second the computer checks the USB for data, so a polling rate of 1000Hz means that the keyboard checks for data 1000 times per second. Then, we place the plunger above the P key and position the camera so that we see when the key is actuated and when the gun in Valorant fires. The camera starts to record a video as the plunger presses down on the key 12 times.
Once we finish recording the video, we analyze frame-by-frame when the plunger exactly made contact with the key and when the gun fired in the game. Since the camera records at 1000 frames per second, each frame is 1 ms, and we count the frames between the point that the plunger makes contact with the key and when the gun fires to measure the click latency. We calculate the deviation between the 12 results to make sure there aren't any outliers or problems with our results. We use an average of the 10 best values to get the latency, and then we subtract the system latency that we previously calculated. However, this isn't the final latency, as we also need to account for the key's pre-travel distance, which we measure before doing this test. Using the speed of the plunger and the switch's pre-travel distance, we can calculate the key travel time that's needed before actuation. We also subtract this number from the click latency to get the final keyboard latency.
For example, if a switch's pre-travel distance is 1.44 mm, we know that the key travel time is 1.872 ms. If we also calculated the system latency as 9.4ms, and if we get an average click latency of 13.75 ms during testing, the final keyboard click latency would be 2.5 ms (13.75 minus 9.4 minus 1.872, rounded to the nearest tenth). Depending on the keyboard's connectivity, we repeat this test over Bluetooth, wirelessly through the proprietary receiver, or wired.
Wired keyboards generally have the lowest latency because they're connected directly to the computer. The keyboards with the lowest latency are generally gaming ones as well.
For wireless keyboards, the best way to get low latency is when it's connected through a proprietary USB receiver. Manufacturers have improved the wireless latency over a receiver to the point that most wireless gaming keyboards have as low latency as wired ones. Some keyboards even have lower wireless latency than wired, such as the Razer BlackWidow V3 Pro. If a keyboard comes with a receiver extender, we place it about 20cm away during testing.
Bluetooth connections are generally reserved for mobile and office keyboards because it results in the highest latency. You shouldn't notice any delay when typing, but it's not ideal for gaming.
There isn't much you can do on an individual level to reduce a keyboard's latency. Switching from a wireless connection to wired will likely reduce the click latency. You can also check to see if your keyboard has debounce time or polling rate settings, as changing them can improve the click latency. If you still feel like there's too much lag and it affects your gaming, you should also check your PC and monitor settings, and if you're gaming on a TV, make sure to set it to 'Game' mode.
Having a keyboard with low click latency can be extremely beneficial to most gamers, and it's also important to know the click latency before buying any keyboard. Your keyboard is just one piece in a line of equipment in your gaming setup, and each piece contributes to the total latency from the time you input your action to when it appears on-screen, so it's important to get a keyboard with low latency.