Even in the world of technology, where messages are sent around the world in a matter of seconds, nothing is instantaneous. With PC gaming, each piece of equipment introduces some sort of delay, called latency or lag. For gaming, you want to have the lowest latency possible so that your actions translate more immediately in-game and the experience feels fluid and responsive. The click latency of the mouse you're using plays a major role in that experience.
We measure the click latency using a USB protocol analyzer and express the result as an average of 205 clicks. We perform this test for each compatible connection type, but only the Expected Connectivity result is used to determine a mouse's click latency score.
We also record a video of this test. This video aspect bears similarities to our Keyboard Latency test. However, it isn't used as part of our measurements. It's primarily intended to act as a visual aid.
Having a mouse with low click latency is extremely important for gaming. Of course, you also need a computer and a monitor with low input lag, but having a responsive gaming mouse can make the difference between winning and losing. Although most people can't visually or audibly tell the delay between when the mouse is clicked and when the action appears on the screen, a mouse with high latency can make subtle differences in games. Especially in online, competitive games, having a low latency mouse can give you an advantage over your opponents if they have mice with high latency.
The mouse's connection type affects the click latency. Generally, wired mice have the lowest latency, and Bluetooth mice have the highest latency. A Bluetooth connection isn't recommended for gaming, but it's still good for office use, and most people won't notice any delay unless the latency is extremely high. Wireless gaming mice that use a USB receiver have become more popular, and technology has evolved to greatly reduce the latency, to the point where some wireless options are as good as wired ones.
Our test uses a large number of data points so we can visualize variation, identify outliers, and produce a reliable average figure that represents a user's click latency experience.
The way we measure click latency is straightforward but relies on several pieces of equipment. We use a dedicated gaming PC, a capture PC, and a Beagle 480 USB analyzer to record the click latency data from each connectivity type. For a wired connection, we connect the mouse directly to the USB analyzer using its USB cable. For a wireless connection, we plug the USB receiver into the analyzer, and for a Bluetooth connection, we plug a Bluetooth adapter into the analyzer. Additional equipment for this test includes a metal connector attached that we attach to the left mouse button, a solenoid attached to a testing arm, and a custom breadboard that incorporates a Teensy 4.0 development board responsible for controlling the solenoid.
Our test also includes a video record of the test and incorporates a gaming context. We use an offline match of CS: GO because it allows us to adjust certain match parameters (like round length) to facilitate filming. The video demonstrates the solenoid arm actuating the left-click button and the resulting weapon muzzle flash from each button press. Randomized behavior is added to the solenoid that produces variation in how long each button press is held and the delay between each button press.
During our test, the mouse is secured in position with clamps, and the sensor is covered with tape to avoid any x/y motion data. An important element of our methodology states that our tests shouldn't open, break, or alter the mouse's ergonomics.
For this reason, we place our connector on the left-click button instead of opening the mouse and connecting it directly to the microswitch itself. This means that our click latency measurements include pre-travel distance. Because of this, we expect our results to be higher than those from other tests and manufacturers' spec sheets. However, our results will be more representative of the actual user experience.
Note that we ensure that the lowest latency settings are used for each mouse tested. This includes using the highest possible polling rate and lowest possible debounce time.
Once all 205 data points are collected for each connectivity type, we discard the first five clicks since there are cases where these are detected before the test has started. In rare cases, we also discard any instances where the data has timed out. This can sometimes result in a total sample size of slightly less than 200, but this is a rare occurrence. With the resulting samples, we plot them on a graph. Lastly, we calculate our click latency score using only the results from the Expected Connectivity type.
Below is a sample of what this graph looks like for a mouse with wired, wireless, and Bluetooth connection types.
We use this result to determine our click latency score for each mouse. Even if a mouse has additional connectivity options, only the expected connection type contributes to the score.
A wired mouse connects directly to the computer and generally has the least latency. Some mice, like the Logitech MX Master 2, have a charging cable but still use their wireless connection when charging.
Wireless gaming mice use USB receivers, which generally have incredibly low latency, some as low as wired mice. Some mice come with a USB extender to place the receiver closer to the mouse. It's because USB receivers tend to have higher latency the further you move away from them, so it's important to have the receiver as close as possible.
Using a Bluetooth connection generally results in the highest click latency. It's why some gaming mice don't even have Bluetooth support, and if they do, they're typically only used as a power-saving option when not in-game. A Bluetooth connection tends to have the highest click latency of the three connection methods, but it's more than sufficient for everyday browsing and productivity tasks.
There isn't much that you can do to improve click latency besides using a wired connection when possible. If you still find that there's too much latency, check the debounce and polling rate settings, or check your computer and monitor settings. If you're using the mouse with a TV, you should make sure the TV is in 'Game' mode, which is usually when the input lag is at its lowest.
Most gamers will look for a mouse with the lowest click latency, so they know their actions are registered almost instantly. A mouse with low latency can make the difference between winning and losing. The latency increases depending on the type of connection, so it's best to use a wired connection or a wireless connection with a USB receiver. It's a good idea to reserve using a Bluetooth connection for everyday browsing and productivity tasks or whenever you want to save battery life.