Amazon K690 Manual page 12

Sensitivity
It allows you to customize the polling rate, repeat rate and the
repeat delay.
Polling Rate:
Repeat
Rate:
Repeat
Delay:
Repeat Rate
Test:
12
Configure the number of times the computer
prompts the keyboard for information. The
default setting is 500 Hz. The possible settings
are 125 Hz/8 ms, 250 Hz/4 ms, 500 Hz/2 ms,
1000 Hz/1 ms.
Configure the repeat rate speed. Low setting
means that the characters repeat slowly when
the key is held down. High setting shortens the
interval.
Adjust how long to wait before repeating the
characters when a key is held down. The
possible settings are 1X: 250ms / 2X: 500ms /
4X: 750ms / 8X:1000ms.
Hold down a key to test the speed of repeat
rate and repeat delay.