Fix laggy key presses
If key presses are slow or laggy, check the system configuration.
On Ubuntu you can configure keyboard repeat interval and delay:
gsettings set org.gnome.desktop.peripherals.keyboard repeat-interval 3
gsettings set org.gnome.desktop.peripherals.keyboard delay 150
Settings → Universal Access → Typing → Repeat Keys
Adjust the delay and speed.
On KDE you can open a window to change the 'Delay' and 'Rate':
On Mac, if holding down a key does not repeat the command (a feature of Mac), you make a key repeat by running this once at the terminal:
defaults write com.sublimetext.3 ApplePressAndHoldEnabled -bool false
On X11 based systems you can directly use
xset r rate <milliseconds_before_repeating> <repetitions_per_second>