We can change the intervals of key repeat and delay until repeat at the System preferences > Keyboard. But you may think it too slow even if you set the minimum values.
We can set faster value with Karabiner.
Or we can set it at a Terminal. My recommendation is following :)
$ defaults write NSGlobalDomain KeyRepeat -int 1
$ defaults write NSGlobalDomain InitialKeyRepeat -int 12
First one is the repeat interval when you keep pressing a key. Second is delay until starting to repeat. 1 is not milliseconds. I’m not sure about the value, but maybe 1 is equivalent to 16 milliseconds.
So the config will get you KeyRepeat -> 16ms, Delay until repeat -> 200ms.
If it doesn’t work, try following. (try true and false)
$ defaults write NSGlobalDomain ApplePressAndHoldEnabled -bool false