# What's Mouse Polling Rate

By Xah Lee. Date: .

USB Polling Rate is how frequent your computer checks for signal from the mouse.

USB Polling Rate is measured in Hertz, meaning, number of times per second.

Many gaming mouses can set polling rate to a high number, such as 500 Hz, meaning, 500 times per second.

The older interface tech, the PS/2 port, does not have polling “problem”. That is, it doesn't periodically check for signal. Rather, any signal is transmitted immediately.

## Default Polling Rate

By default, USB polling rate is 125 Hz in Microsoft Windows and Linux.

( 125 Hz is 125 times per second. 1 second divided by 125 is 0.008. This means, the computer check mouse signal every 0.008 second)

## Does Increasing Mouse Polling Rate Matter?

Some gamer claim that 500 Hz polling rate creates less lag, but that may just be psychological.

Here's a table of polling rate and delay.

polling rate and delay
counts per sec (Hz)delay (in second)
10000.001
5000.002
2500.004
125 (default)0.008
1000.01

So, the question is, do you move the mouse fast and accurate enough such that a delay smaller than 0.008 second makes a difference?

For some gamer, they say they can feel the difference between 125 Hz and 500 Hz, but not above. The logic might be like this:

1. If you are playing first-person-shooter game, then you may set mouse DPI low, such as 800 DPI, this give you precision.
2. Then, you'll need to make big mouse movement, such as one arm swipe, to turn 360 degrees.
3. Say your mouse move 6 inches in 0.5 second. (so, 12 inches in 1 second.)
4. In that second, if you have polling rate of 125, then the computer receives 125 signals.
5. The computer gets 1 signal every 0.008 seconds. (1/125 == 0.008)
6. Now, there's lag of online games. Let's say 20 milliseconds on average (0.02 second). That is, it has that duration of delay for the info from your computer to make a round-trip to the game server and back.
7. So, from the moment your mouse sends 1 signal to the time you see on screen, it may be 0.008+0.02 == 0.028 seconds.
8. Your 360 degree turn, may not be smooth, because each display video frame update, there may be a lag as much as 0.028 second. (by the way, typical refresh rate of display, is only 60Hz, (or 1/60 == every 0.0166 second))

Therefore, increasing the mouse polling rate might make things a bit smoother.

But i doubt it!

Note: higher polling rate sucks battery life.

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